High-performance ECU file set for the 2000 Audi TT 1.8T 20V with Bosch ME7.5 (software 354503 / 0002). This package includes two modified calibrations: Stage 1 for mildly tuned vehicles with stock K03 turbo, and Stage 3 designed for K04-001 or hybrid setups with larger injectors and intake/exhaust upgrades. Perfect for DIY enthusiasts or professional tuners seeking dyno-verified gains and road-ready reliability.