Add another vote for RB. My WS7II has over 5 gals on it, still great pinch, easy to tune, no flame outs Just put a rear bearing in, didn't really need it just some PM. I ran against some GRP's on Sat, and was going to buy one, till I seen them run it person. They are really pickey to air temp. changes. And my RB pulled them on the straights and hung with them in the tight stuff.
So I am staying with RB, But I am looking to get a new Ninja just to see what it's about!