If it dies when accelerating thats a tuning problem,could be the HSN is to lean. I was having problems getting my XP to shift until I took the transmission out and noticed the shifter mechanism (little silver disc thingy) was put in backwards so no matter how much you tweaked the shift screw it wouldnt matter. After I fixed that its just a matter of adjusting it to shift when I want. If you need help taking it apart and checkin it out lemme know.

About the tuning,ehroof posted a link to some excellent video's in the 1/10th scale buggy thread (one of the last pages) also this link has alot of useful info and makes tuning the LSN a piece of cake along with the rest of know how:

http://www.*********.org/cars_eng-tuning.htm