to be honest, your best bet is to go to the local track and see what those guys are running... there are quite a few different classes to race in. Also, it helps to see what the other guys are running because if you have the same chassis, you can borrow/swap parts when stuff breaks. Our club has a mix of every car you could think of.... the most widely used at the current moment is the TOP Photon though. They are still expensive (about $360) but they are extremely competative. Most tracks i've visited run a 17.5 stock motor (I like the Team Epic Duo 3 because it's one of the best and it doesn't use a plastic end). The ESC is usually a Tekin RS (that's what most are using at my LHS) or an LRP. A 2S lipo will be what you need and your club will most likely tell you which tires you need to run to be competitive.