This might seem like a silly question, but what problem are you trying to solve by moving to these other chassis (Exotek, smokem, etc...)?
I have a 416WE and a 416X and not sure what I am missing. The cars seem to work pretty well with the stock chassis' on them. Why anyone would move away from the quality of Tamiya is beyond me. LIPO's fit in my car great...just a little bracket (Which took about 1 minute to build) for the neg. battery connector and battery works just great.
What am I missing?