porting of the heads, tubular or fully ported manifolds, and cams that spread out the power band (The JWT 400+ cams spread the power out at lower as well as higher RPMs), the 700s would be fairly laggy for circuit racing (IF that is like road racing in the States). Your best all around choice for a good responding turbo that makes good power and is very responsive would be the sport 500s or 530 ball bearing turbos from JWT. The cams, headwork, and exhaust manifold modifications (either Greg's tubular manifolds or a good porting of the stock ones) would make a nice complete package for strip and track. Take care, Mark