Need to replace Mamba motor in FLM Rusty

[dadgummit]

I have a full FLM Rustler that weighs 6 pounds including battery. Right now it has a MM 5700 system and I was thinking on replacing the motor with something more efficent. I was looking at the Lehner basic XL series (either 3600 or 4200KV since I have a ton of 6 -7 cell nimh packs). Will the Basic XL pull too many amps for a nimh pack?

The rusty's spur gear is a 48 pitch so I think I am really limited to the basic XL (with a 1/8" shaft) for the motor I can use. Does anyone sell 48 pitch pinions with a 4mm or 5mm bore?