I used to pre-load the cluth slightly and bounce the rev's between 5000 to 5500. When I finally launch I try and slip the clutch as the revs are coming up (kind of hard to explain it). I found without a stutterbox if you bounce the rev's with your accellerator pedal and launch as the rev's are coming up it builds boost better than if you hold it at a set RPM and slip it. That's how I got my pretty much stock Talon to run it's 12.99.
Then again it all could just be in my head
