RE: O.S or Novarossi?
the bottom end on an 8 port is a joke. that is an rpm tuned engine, not a torque tuned one. If you can afford it - go with the RB Concepts WS7 II. This engine probably has the greatest bottom end on the market. If its too much for your wallet, go with the OS Max .21RG - cheap as hell, and just insane bottome end torque. not very fast on the top end though.