Slash is pretty durable and won't break unless you go full speed into a curb or something like that. The things that could break are the rear bearing carriers, and possibly popping off the shock caps. Both are quick fixes and only cost a few $$$ to replace. 2wd is loads of fun, waterproof electronics, etc. and less $$$ than the 4wd; if both are Lipo powered they are equally as fast. Sounds like 2wd would be your best choice.