[super__dan]

I've not tried Lipo either, Chris has and says a 7.5L is almost too fast so you don't want any more than that for defo.

The pins catch on the 81 spur if you are upside down and rev it at all. The quickest and easiest way is to run the 78 spur that almost everyone I know uses, almost moves the motor back a wafer which doesn't harm any.