Well, I did a lot of looking before I picked up my AE Nitro TC3 2speed 4wd. With the right getup, this car has and will do 70+. I have decided to go with the MT .12 Big Head. Mugen Seiki mill. Essentially a Nova Rossi. Italian made. Steady under 200 degrees F.. 5 port. Etc Etc.
Anyhow, if you have a programmable TX or one you would like to use. Then get the kit car. I got the 2031. 4wd 2speed. Made for rear exhaust bump start mills. But get the model for your needs.
As far as electrics, Novak XXTra Synth. FM RX, Futaba 'standard' servos to start with. Then I go to the HiTec servo that I will need for the job. I wont know that until I have driven it for a while though.
Foams are good for onroad. Most come premounted and trued. Which takes a lot of guess work out of proper tire mounting. Something that truel affects performance. 60/40 front/back should be a good overall foam density to start with.
Start with stock suggested settings first. THEN, start messing with it. Only one thing at a time and see how it affects performance.