I am thinking about buying the Losi XXX-NT AD2 and i was wondering what engine do i buy to race with? I am completely clueless... Do the nitro classes have different engine rules and what not? Anyone from Capital City RC in Sacramento on here that can help me out? Also how hard is it to actually put the engine into the car and will it just bolt right in or am i going to need a bunch of extras? thanks for your help