Alright, have myself a 2001 audi s4, had it for abouta month so far, got a boost guage, exterior wise the car had rims, a stripe lowered a little, looks like it had mods done to it before i bought it...now for the question..boost gauge reads about negative 15-20 at idle, regular driving(no boost or hard throttle) RPM's are ALWAYS at 900 no rough idle or anything, but I read a stock audi is rated at about 250 at the crank so maybe a little less at the wheels maybe its just me but mine seems MUCH quicker, and at wot shifting at about 6800 6900(tiptronic) im making about 15 psi,I know where the ECU is under the pass seat..DoI possibly have the GIAC or APR chip? Any way to tell without pulling it out..thanks guys