I've thought about making a racing pipe that goes from the DP into a 45 bend and either a turn down tip or slash cut that dumps out under the passenger rocker panel infront of the rear wheel.
Basicly a open exhaust for race nights, or playing around. No muffler, and it's shorter so it should flow excellent. (Would be cheap too.)
The other option is a new DP that dumps just behind the front wheel, and is just long enough to be slash cut right at the rocker panel. (Nascar style with two or three square tubing tips to keep ground clearance excellent, and it kind of forms an exhaust panel exit. If I used 1.5x2 tubes, it would look nice, and flow plenty, problem is the merge area would need to flow right or it would cause restriction. The easy way would be to run the DP straight back, and have the box tubing angle off the pipe with the last one tapering the pipe to the rear wall of the box section. (Like a 2JZ intake manifold.)
Heck screw the fancy tips, just put a turn down under the car, and dump it there. It would help to keep it quiet too. (Besides, it's a great leaf blower that way.... )