Rob
welcome back, this hobby always has a way to suck a person back in.
as when you raced the best way is to go to your local track and see what people are running and what classes have the strongest support. same goes for the chassis, what is best supported will save time and money. getting back in after a few years away, brushless technology and lipo's are a thing of beauty, no more cutting comms, peeking ni-mh or even ni-cd if you were using them. as with all things........evolution is good
the old stock brushed motors are replaced by 17.5 brushless
hope this helps in some way