LOSA1550 I think is still available.
I was lucky enough a few years back to get a full alloy bellcrank setup, but prior to that had ran the drive pin mod. Essentially you drill from the top down and insert a steel pin (similar to the ones used on the rear axles which drive the wheels), this plus a smidge of superglue helps stop the arm slipping on the splines
Explained here
http://www.petitrc.com/setup/losi/se...kModification/