The difference between stock and mod 1/10 2wd off road is: mod is faster and more difficult to drive for a novice, in your case start with a stock motor (17.5 turn). I'm not familiar with stock 4wd, maybe it exists but we don't have any classes for it around here. There is no such thing as stock 1/8 scale. Use trackstar/hobbyking equipment at your own discretion. They come from China if they ever come at all, I will not personally use hobbyking anything after dealing with their lack of customer service. Some use them with success, I don't recommend them. I would stick with something from your local hobby store that you can get assistance with or with a well known online store like Amain.com, towerhobbies.com, SMC-racing.net, etc...