I would suggest an OS engine there fairly cheap and they're pretty good engines. For a little more you can get a novarossi. I love those engines.

If you buy just the engine then that's exactly what you get. Get a tuned exhaust pipe they are worth the money. I noticed a big increase in overall speed and especially performance. But if your car kit comes with a single speed transmission get a multi-speed transmission they have a more bang-for-the-buck quality. Especailly in the speed department.

A glow engine uses a glow plug (usually on the top of the engine). This works like your typical car spark plug. You have to use a heating device which is usually re-chargeable and place it over the glow plug to heat it up. You then turn the engine over using either a pullstart (like on a lawnmower or chainsaw) or a starter box which has a wheel on top which spins the flywheel when you press down. The heat from the glow plug sparks the gas which forces the piston to move which turns the shaft which turns the flywheel and so on.

Nitro cars get between 10-15 mins. of driving time out of one tank of gas. Which is longer than it sounds. If its shorter than that than you're most likely running rich, or too lean if its longer than that period.

I couldn't help you out about what you need. Most incomplete kit cars need a radio (sometimes the servo's too) an engine & maybe an exhaust. I would just go down to your local hobbie store. they should be able to help you out.

Oh a few words of advice. Don't be too excited about driving your car right away. You need to break in the engine. I usually waste about 5 or 6 tanks before I go balls out. The first two you basically want to just run the engine. The next two you can drive the car at very low speeds. And the next one a little faster with some steady speed increases and the last you can drive a little faster with some short full speed intervals. Don't expect to get your engine in tune right away. I always break my engines in on the very rich side. Not so rich that it won't stay running or even go. Good luck and have fun.