I’ve recently had my car re-mapped, it now produces 345 bhp and 345 lb/ft.
(03 Sti UK, 3” APS exhaust with sports Cat, uprated fuel pump, cold air induction kit)
When I put my foot down in 4th, 5th and 6th at about 3000rpm there is a flat spot, it feels like it’s miss firing and I can hear a chirping noise. I’ve been told that it’s probably compressor sugre. The car felt slightly quicker when accelerating from 40mph in 4th when it was standard (265bhp). Is this normal and is there anything I can do sort it out?

 

I got the very same thing on my old evo 7! I assumed it was the dump valve leaking. Didn't do it all the time though and I sold the car before I got it checked out. The evo was running about 400 bhp with an apexi power fc ecu.

Maz