I run the GT4 W with a host of options, aluminum shock mounts,braces, brake bracket, and shocks lowered motor mts. I have an RB 5 port turbo with 15/48 first gear (gotta change) and a stock 2nd gear setup. diffs front and rear. Lightened clutch to hit harder. my biggest challenge right now is powering out of the corners I have way too much wheelspin. rubber tires sorex (temperature driven on type)
I also have a Reflex NT I run on foams which is also blinding fast with a stock MT12.
Here in socal I have lots of sun to run every weekend.