I used to race them, and have a couple in my closet. Here is what I learned:
Gas is much more fun...you've got different engine options, multiple gear transmissions, air intake upgrades, etc. Just like a real car, but they are quite expensive. A good gas engine will cost you close to $200+. They actually run on nitro methane mixture, but you can't beat the noise and power. My main car is gas, I have upgraded suspension, new engine, headers, exhaust pipe, air filter, tires, wheels, body and other misc things and have well over $1,000 invested.
Electric is cheaper and easier to upgrade, lightweight, and you can't beat the torque.
The bodies will fit either one, they are fun to paint, but take a great deal of time.
Really ask yourself, how much time are you going to spend on this. I don't regret buying mine, I raced it a bunch of times and did quite well, but just don't have time for it anymore. So, now I have a $1,000 toy sitting in the closet that is collecting dust.
If anyone wants to get off to a good start, I would be willing to sell one heck of an HPI Nitro car starter kit.
Hope some of this stuff helps. If you have any specific questions, feel free to PM me.
