I also didn't modify the car, and it drives good. I ran it this week at a tiny 1/10th scale electric track and the car got around pretty well. I changed the caster to the front position to get more low speed steering through the tiny hairpins. The motor ran alot cooler because the track was to short to run full throttle.

@invrtd, I wrote a build report on my website. It is in dutch but there is a picture gallery so you can see all the parts and how they are fitted.

I went back to my normal track today and ran the car again with 16/55 gearing and the speed is close to that of the nitro cars.