rdorman, It was suggested to me and I will go that direction. When I was a kid our street cars did 350 to 400hp and used 2" od pipes. I assume anything over 400hp needs to breathe better. Look at
http://www.spintechmufflers.com/
they make 3"x2" oval pipe and mufflers that should hug the body but still increase the exhaust flow. I plan to exit before the rear tires, way to much restriction going over the top. Look at the ERA site and the undercar exhaust, it is makes a big loop and only works with inboard brakes.
The custom header will be the tricky part.
NAV, Beautiful car, tan interior?
Gary