hey guys bought this for the kids runs good smokes a tiny bit-pretty sure valve guide seals by the way it smokes- other than that runs like a freaking top. the owner before me put his stock 25's of his Honda on it it pulls them ok . lil bit underpowered in some situations. my question is would I be better putting an exhaust,jet kit,and k&n filter or finding a same year 350 big bear engine to swap in should all be the same or does anyone know ?