RE: what car can handle brushless
Just as a note here... any car can handle brushless. You need to be a bit more specific. For instance, a 17.5t stock brushless is about the same as a 27t brushed which is what a lot of on road cars come with stock. A 3T brushed motor is much faster than a 7.5t brushless.
The great benefits of brushless are the better efficiency and lower maintenance, any rc car would benefit regardless of how fast you want to go.
If you're talking a 5700kv motor on 3S lipo then that's another matter entirely.