This thread is kinda dead but I have this same problem. It only does it as I'm slipping the clutch rolling into gear...It's kind of annoying and I feel like it shouldn't do it. Should I see about clutch replacement? I would get a SVT clutch and flywheel...the car has 98,500 miles so that's really good for an OEM clutch. I don't experience any difficulty shifting or anything other than the chatter, but it'll have to been done sooner or later, doesn't matter. Sometimes it does wanna pop outta first on me though, very rarely
that could be a synchro right?