now not to be a dick, but if you are so wise on the way's of R/C why run an engine without a pipe on it? what does that prove? and "the engine vacuum helps pull fuel in" is true but it only brings a fraction of the fuel in that it should. The tuned back pressure from a good tuned pipe changes tuning on an engine greatly.
Also why leave the glow driver on the plug after you got it running like melting them?
Also why aluminum A Arms? you like spending money when you tap a wall or a curb? they bend VERY easy and cause your car to go out of tweak almost the instant it hits the track.
Being a dude who raced competitively a mod'd RS4 for 2 years I know where some weak points are: and they are simply the drive line. You are going to snap the dog bones in the center, and possibly burn down gearing in the diff's amazingly fast. Lash will build rapidly cause of the design and materials HPI used and will make the car very breakage prone. The rear dog will snap quite frequently with that much power.
The R40 is a much better bet (even though I think the R40 is a copy of a copy of a copy)
Heres a pic of the RS4 I used to race:
None of that blingy aluminum stuff where it didnt need to be... It's a RS4 w/ a custom center shoe type 2 speed, one way, hardedned front and rear bits, and a 7075 3mm beveled chassis... it was a stout machine.
Heres the baddie FW-05RR that replaced it (shown after a year of running it):