It didn't pop out of the c-clip. The actual flange that the BOV sits on, popped out of the I/C pipe. My turbocharger then started making a really high pitched whistling sound, versus the regular spool sound, thought my turbo crapped out on me. Found out it was the BOV.

Only other things I'd check, are the actual recirc hose (makes sure there are no kinks and that the two ends of the recirc hose are sealed properly and the actual diaphragm of the BOV itself.

Sounds like your car is stumbling due to air/fuel mixture problems, the the BOV is most liekly causing. BOV may not be dumping the correct amount of air back into the intake for some reason. THE HKS SSQBOV should be having a "flutter" sound. Mine has alkways had a flutter sound. Well, it can actually vary, depedning on the boost level and RPMs, sometimes it;s more of a whoosh, sometimes more of a flutter.