a decent race engine is easy to tune and all. i have an STS and its easy to tune but an jammin JPX 21 is even easier, those things fly, to much power IMO but i ran it on a Jammin X2 CRT for a while now its going in my buggy. if you get a half way decent race engine i think it would be way better.
however electric is cheaper in the long run, no buying fuel ever week. but i have seen to many problems with something burning up and ruiining everything. if your racing make sure you can even run them. i think electric is cheating in quals but the main i dont care because they wont make it the whole time before a battery swap or just run out of juice.