For what you would pay for a Chinese RTR engine, you can get one of these engines. They're fantastic runners, easy to tune, and are high quality. Coupled with a 41032 header and 9886 pipe, they're a beast in disguise. If Supertib sees your post and chimes in, he could give you better info than I can, but I know these engines are great. I have one myself.
Engine: http://novarossidirect.com/LEGEND28-8_p_3226.html
Manifold: http://novarossidirect.com/41032_p_2637.html
Pipe: http://novarossidirect.com/51021-EFRA-9886_p_2667.html

The pipe and manifold I listed are really to get the most out of the engine's capabilities. Using the stock Ofna header and pipe will work, but there would be a chunk of power left on the table - especially if the pipe on the car isn't even an 086. If you want good bang for the buck, this is the way to go. If you're on the fence to stay with nitro, then a cheapie RTR engine might be better for you.