I have a 03 wrx and had a brand new 6speed sti tranny from the 07 sti and a brand new exedy stage 1 sti clutch with a stock oem resurfaced flywheel from an sti. as far as power its got a vf22 with pinks and a walbro fuel pump, and grim boost controller solenoid and professionally tuned to 20lbs (which it rarely sees cause i don't like to beat on it unless i really want to show the guy next to me what i got but that is very rare) So anyways i was in one of those rare moments where i let it loose and as i was getting out of first gear and slam-ed it into second i felt like something slam-ed against something. It wasn't too harsh but i definitely felt something the car other than that feels solid, just that slight slamming noise and feeling has me concerned, I will take it back to the guys that did all the tranny work and clutch to check it out but if u guys could give me some ideas of what i could check for before i take it in i would greatly appreciate it. Thank you.