So I noticed something a few weeks ago right after I spent the weekend at an autocross.

My car seems MUCH spunkier afterwards. Boost comes up sooner (noticeably), car has WAY more midrange, seems to run smoother/better all around. After driving it for a few days (of just normal around-town driving) it seems to lose some of the spunkiness. Takes longer to spool, doesn't seem as strong when at WOT, etc.

Think maybe it's running too fat in the midrange and/or part throttle? I generally don't drive all that aggressively around town (maybe lay into it once or twice but for the most part I'm pretty calm.) Wondering if maybe it's just loading up inside and after pounding on it a little at an AX it kinda clears out?

Car is mostly stock. Welt chips, 3" exhaust, LBE. Stock 2.5bar FPR.

 

I have the exact setup. Mine does the same thing. I think it might be the chips. I have a cat bypass also and the exhaust starts to stink and the performance goes down if i don't go for long drive (beat run). The car also backfires like crazy when i let off the gas.