C7.5 RS7 Modification Bible
Complete guide from Stage 1 to 1000+ HP. Track your build progress, explore tiers, and plan your modifications.
Overall Progress
0 / 0 mods completed
First
Preventive Maintenance
Before adding a single horsepower, address the 4.0T's known failure points. These items prevent expensive failures and should be completed before any power modifications.
Turbo Oil Feed Strainer Relocation
~$500 (JHM kit)
The platform's most notorious weakness — mesh screens clog with coked oil as early as 40,000 km, starving turbo bearings. Turbo failure from blocked screens costs €6,000+ versus ~€500 for preventive relocation.
PCV Valve Check/Replace
Part of inspection
Check the PCV (Positive Crankcase Ventilation) valve — failures occur around 60,000–80,000 miles, causing vacuum leaks, misfires, and accelerated oil consumption.
Carbon Cleaning (if 80,000+ km)
~$400–800
Direct injection engines inevitably build carbon deposits that reduce throttle response. Recommended for cars over 80,000 km.
Switch to 5W-40 Oil
~$80–120 per change
Use 5W-40 exclusively (better thermal stability under boost than 5W-30). Top choices: Liqui Moly Leichtlauf High Tech 5W-40 or Motul 8100 X-Cess Gen2 5W-40. Change every 8,000 km maximum on a tuned car.
Tier 1
Foundation Mods Under $300
Every tuned RS7 needs these foundational modifications. Zero to minimal NVH increase, immediate driving improvement.
034 Motorsport Drivetrain Mount Insert Package
$285 (034-509-6001)
Billet aluminum inserts fill the voids in factory rubber transmission and differential mounts, eliminating drivetrain slop under acceleration and shifting. Zero NVH increase for transmission, minimal for differential. Install takes ~45 minutes.
NGK Racing Spark Plugs R7437-9
$320–440/set of 8
One heat range colder than OEM. Community-standard plug for any tuned 4.0T. Gap to 0.024" (0.6mm) for Stage 1+. Change every 15,000–20,000 miles on Stage 1.
SRM Throttle Body Spacer
$129
Thermal protection for fragile plastic components between turbo outlets and throttle bodies. Not a power adder — it's a heat barrier extending component life on tuned cars.
APR Red Coilpacks
$360–400/set of 8 (MS100219-KT8)
6% more spark energy over stock through increased copper winding diameter and enhanced neodymium magnets. Not strictly necessary for Stage 1, but worthwhile as a reliability upgrade during plug service.
Tier 2
ECU & TCU Tuning — $650–$1,800
The single best modification for your RS7. A Stage 1 ECU tune delivers the greatest return on investment, adding 100–160 crank HP for under $1,000.
TCU tune is essential: Without it, the transmission actively holds back your ECU tune's potential. TCU tune raises shift points to 7,200 RPM, increases launch stall RPM, and raises torque limiters.
ECU + TCU Packages (Recommended)
JHM ECU + TCU Combo
~$1,050 (+ ~$100–150 for cable)
Best overall value. Includes all stages (1–3), all octane maps. TCU raises shift points to 7,200 RPM, increases launch stall to ~3,000 RPM. Reported "almost a full second faster in the quarter mile."
Jackal Motorsports ECU + TCU
~$810–850 total
Budget pick with ECU + TCU included, all stages, free upgrades forever. ~55 WHP / 122 WTQ gain. "For the money there's nothing better."
ECU Only (Pair with separate TCU)
DS1 (Dyno Spectrum) ECU
$1,299.99
Best for future-proofing. All stages (0–4), all octane maps including E85 flex fuel. WiFi device flashes via browser in 3–4 minutes. Supports real-time tuning, rolling anti-lag, virtual cockpit gauges. Dominant platform for high-power builds.
APR ECU Tune
$999.95
Best for conservative "set and forget." Longest-established tuner with proven reliability. Stage 1 on 98 RON delivers up to 722 HP / 849 lb-ft. Note: APR does NOT offer ZF 8HP TCU tune for RS7.
Revo ECU Tune
~€500–800
Best for local EU dealer support. UK/EU-based with largest European dealer network. Stage 1 only. Ideal for single-visit install with local backup.
Tier 3
Intake & Exhaust for Stage 2 — $377–$3,200
Downpipes are the gateway to Stage 2. This tier unlocks the hardware potential for your tuned engine.
Downpipes
ARM Motorsports Catted Downpipes
$697
Recommended for street use. SS304 stainless with 200-cell high-flow cats. Claims +37 WHP / +42 WTQ. Preserves catalytic converter function for annual inspection.
REDSTAR with HJS HD 200cpsi Catalysts
~$800–1,400
Most EU inspection-friendly option. HJS is a German manufacturer with TÜV certification. OEM X-crossing layout maintains factory exhaust routing.
Midpipes & Catback
ARM Midpipes
$377–397
Replace factory resonators with straight-pipe sections. No CEL (downstream of O2 sensors). "Night and day" sound improvement with enhanced turbo spool acoustics.
Milltek Valvesonic Catback
$2,629–3,115
Most popular among EU owners. Resonated for refined OE+ sound, non-resonated for aggression. Retains factory valve control through MMI/Drive Select. 304L aircraft-grade stainless.
APR Catback CBK0010
$3,199.95
Cast valve housings, OEM electronic actuators, CNC-bent tunnel brace adding chassis rigidity. Note: C7.5 requires RS100004 valve extension harness ($29.99).
Intakes
SRM 2.5" Intake
$595 (short) / $895 (long)
Largest intake runner available for the platform. Claims 30–40 HP at redline by reducing inlet depression. Note: 3–4 week lead times common.
ARM Stage 2 Intake System
$867
Includes billet 62mm turbo inlets, dry media filters, and aluminum heat shield. Claims +27 WHP / +32 WTQ.
Eventuri Carbon Fiber Intake
~$2,450
Premium option with independently verified gains: 15–19 HP, 13–17 lb-ft, 0.4-second improvement in 60–130 mph. Full sealed carbon fiber airbox.
Tier 4
Cooling Upgrades — $560–$2,995
The 4.0T's hot-V configuration traps enormous heat. Cooling is the difference between a car that makes power on one pull and one that's consistent.
Water-to-Air Path (Recommended for Stage 1–2)
JHM Performance Heat Exchanger
$699.95
The single most important cooling upgrade for Stage 1+. Dual-core, quad-pass design. Bolt-on install in under 5 minutes with self-drilling bolts. Do immediately after tuning.
SRM EMP Brushless Water Pump
~$995
Widely regarded as the best single cooling upgrade for the platform. Reduces IAT rise over a quarter-mile by up to 50% by dramatically increasing coolant flow.
SRM SPAL Fan Kit
~$500–800
Adds active cooling to heat exchanger for low-speed and staging scenarios. Essential for repeated pulls, drag racing, or track use.
Air-to-Air Conversion (700+ WHP)
SRM Air-to-Air Intercooler Conversion
$2,995
Replaces entire W2A system with front-mount CSF core. IATs never exceed 10°C over ambient. Major installation — replaces crash bar, requires bumper removal. Worth it for 800+ WHP builds.
Tier 5
Fueling Upgrades — $199–$1,495
For ethanol and high power builds. E30 blending delivers ~104–105 effective RON with charge cooling benefits, adding 20–40 WHP over 98 RON alone on stock turbos.
Estonia note: E85 is not available at any public fuel station in Estonia, Latvia, or Lithuania. Nearest retail E85 is in Finland via ferry. Practical approach is E30 blending with industrially sourced or Finnish-purchased ethanol.
SRM Fuel Line Re-Route Kit
$199
Required for any ethanol use — factory rubber lines degrade with alcohol exposure. PTFE lines also support flex fuel sensor installation.
SRM Flex Fuel Sensor Kit
$199
Continental Mini sensor with 10ft harness, designed for DS1 integration.
Autotech Dual HPFP Kit
$679.90
DLC-coated, match-ground pistons for both high-pressure fuel pumps. Necessary for E85 or turbo upgrades; not needed for Stage 1 on pump gas.
SRM Port Injection Kit
$1,495
Adds 4 port fuel injectors (850cc to 2000cc options) with CAN-bus controller. Unlocks 1,000+ WHP on ethanol. Requires DS1 Enhanced OTS calibration.
SRM Dual Brushless LPFP
$1,495
Adds second fuel pump in tank for sustained high-flow demand. Only needed for big turbo E85 builds exceeding ~700 WHP.
Tier 6
Turbo Upgrades — $1,495–$12,000+
When stock turbos become the bottleneck. Stock RS7 turbos max out at approximately 550–600 WHP on Mustang dyno with full bolt-ons and E85. On 98 RON, the practical ceiling is 480–530 WHP Mustang.
SRM +4mm CHRA
$1,495–1,844/pair
4mm larger compressor wheel in factory housing. Power ceiling rises to ~650–700+ WHP on E85 with full supporting mods. Slightly later spool but significantly more top-end.
Weistec W.3 Turbos
$2,804–3,299/pair
Requires sending in your turbos for modification (not core exchange). Realistic ceiling ~650–750 WHP with full supporting mods and E85.
CTS Turbo Stage 1
$1,620/pair
Brand-new turbochargers (no core exchange needed) with 48.6mm inducer billet compressors. Claims 780+ HP capability. Journal bearing design.
Pure Turbos Stage 2
$4,595/pair (+$3,500 core)
Verified 781 WHP / 823 WTQ at 31 PSI in documented build by Eurowise Performance/BoostedEuro.
SRM850 / FE Performance Full Package
~$8,000–12,000+
Complete package: +4mm CHRAs, exhaust manifolds, port injection, intakes, LPFP, flex fuel, wastegates, DS1 + ETSPEC TCU. Verified: 838 WHP / 744 WTQ Mustang (~900+ WHP DynoJet). The benchmark street package.
SRM HIGH VACUUM Wastegate Actuators
~$699
Replace stock plastic actuators that fail under boost above ~26–28 PSI. Needed for Stage 3+. Stock wastegates adequate for Stage 1–2.
Tier 7
Drivetrain Protection — $100–$10,000+
Protecting the ZF 8HP transmission. With a TCU tune, the transmission handles ~800 lb-ft reliably for street use. Beyond ~1,000 HP, shift quality degrades and a built transmission becomes necessary.
Transmission fluid: Change every 40,000 miles minimum (ignore Audi's "lifetime fill" claim). Tuned cars benefit from 25,000-mile intervals.
JXB Performance Driveshaft Carrier Bearing
$329.99 (C7001A0)
Critical preventive maintenance. OEM carrier's thin rubber degrades under torque, causing driveshaft misalignment that can destroy rear differential. 2-piece clamp-on design, no driveshaft removal, no significant NVH.
JHM Carrier Insert (Budget Option)
~$100–150
Budget option requiring no cutting. Good entry-level drivetrain protection.
Differential Fluid Service
~$80–120 (BLAU kit)
Change every 25,000–30,000 miles on tuned cars. Use RAVENOL VSG 75W-90 for front/rear gear oil, RAVENOL DTF-1 for rear sport diff, RAVENOL AWD-TOR for center Torsen.
Built ZF 8HP Transmission
$9,999+ (Pure Drivetrain Solutions)
Only needed above ~850 lb-ft for aggressive driving. E and D clutch packs fail first under extreme torque.
Tier 8
Suspension & Handling — $166–$6,000
Lowering without losing your premium ride systems (DRC + adaptive air suspension). Converting to coilovers would eliminate both systems.
034 Motorsport Adjustable Lowering Links
$166 (034-401-Z067)
The definitive answer. Four billet aluminum links trick air suspension sensors into sitting up to 50mm lower while retaining full DRC functionality and all MMI ride modes. Alignment mandatory after install.
034 Density Line Adjustable Upper Control Arms
~$500–600/pair
Correct excessive negative camber caused by lowering. Necessary at drops beyond 25–30mm to prevent inner tire wear.
Eurocode ÜSS Sway Bars
~$499/set (EC0202-0501R)
Transformative handling improvement. Front 32mm / rear 25.5mm with 2-position adjustability. "So flat in the corners, almost tossable" with "noticeably less understeer."
034 Sway Bar End Links
~$100–175/pair each
Recommended alongside sway bars or any lowering to maintain proper geometry and prevent binding.
KW V4 Coilovers (If DRC Fails)
~$4,500–6,000
Community-preferred replacement if DRC eventually fails (struts ~€1,000–1,400/corner). Requires DRC decommissioning kit from gepfeffert.com.
Tier 9
Braking with CCB System
Your carbon ceramic brakes are already the ultimate braking hardware. Focus on consumables and fluid.
Pagid RSC1 Pads
~$600–800/axle
Go-to aftermarket compound for CCBs — suitable for both street and spirited driving with good rotor friendliness. For serious track work, step up to Pagid RSC2.
Motul RBF 660 Brake Fluid
~$17–24/500ml
Highest dry boiling point (617°F / 325°C). Change before each track day. Need ~1–1.5 liters for full flush.
Stainless Steel Brake Lines
~$150–300/set
Goodridge or StopTech. Requires CCB-specific fitment verification. Lowest-priority brake upgrade — fluid and pads make far greater differences.
Tier 10
Cosmetics, Wheels & Interior — $150–$12,000+
Aesthetic and interior upgrades. CCB calipers require minimum 20" diameter wheels — always confirm clearance with manufacturer.
CCB-Compatible Wheels
$2,400–12,000+
Popular: 20x9.5 ET25–40 with 275/30R20, or 21x10.5 ET30–42 with 275/30R21. HRE FlowForm ($2,400–3,600), Vossen ($2,500–4,500), or HRE/BBS/Forgeline forged ($5,000–12,000+).
Carbon Fiber Exterior
$150–2,000+
Karbel Carbon (premium dry pre-preg), Aero Republic (widest selection), or German Car Accessories (budget). Front splitter $600–900, rear diffuser ~$1,100–1,320, mirror caps ~$150–350.
P3Cars V3 Digital Vent Gauge
$389 (3P3AC7X)
OBD2 gauge in factory air vent. Monitors boost, coolant, AFR, IAT, timing, EGT, battery, RPM with shift light. Plug-and-play, 10–15 minute install.
OBDeleven Coding Tool
~€50–100
Made in Lithuania. Popular codings: exhaust flap control, needle sweep on startup, lap timer, comfort blinker, video-in-motion. More powerful than VCDS for quick one-click apps.