My built y8 has run fine since its last build, about 6 mos. THe other day, i swapped a bunch of bolt-ons for new ones (new dc header, tossed my lightspeed, new dc intake, tossed my old OLD aem...) start the car up its fine, drive it down the road and it sounds like a little like its missing from 2k rpm to 3500 rpm. Keep in mind, car runs perfect, idle is perfect, steady @ half an inch, car blows nothing when i get on it, etc... One option is my exhaust is super old, like 96 old, its a beat up tanabe. since the exhasut is old and has tons of lil problems with it, i am thinking it is a resonace that is making it do this at light/ mid throttle from 2k-3.5k. did compression test, 270 270 260 230. #4 is a little low, i am going to go over valve lash and see if one of them is too tight, but other than that, is it possible that i could have smacked a valve sooooo slightly that is is doing this? usually when i hit valves, in the past, the valve stems on these honda valves is so slim that it would make the cylinder BAD, **** idle, misfire code etc...motor, other than slight sound, runs fine. what do you think?