To be honest Dave, our current team/test driver has been running the std vapor kit with our siim/sirio cl7b engine.
He run it at the first nitro X meeting this year and came 2nd in the A behind a kyosho driver. the car performed very well.
Ive even got a testing video of him down at our local track along with some pics:
http://www.youtube.com/watch?v=tn1Br3ucGnA
Jamie.....