I say get the RS-R Exmag Gt2 here is some pics and the link to the site.
It uses a streight pipe design so it eliminates as much curves as possible.
http://www.rs-r.com/exmag_gt2.htm
The ultimate in exhaust performance is the GT2 series. This exhaust line is specifically designed to omit useless bends to provide the straightest exhaust pipe route possible. Also redesigned for this exhaust system is a unique slip fit design, giving this exhaust the look and performance of true racecars. This is the exhaust system that will provide significant gains in power for your modified vehicle.