That's one of SW's cars. Well, partly his anyway. DSE's website has hundreds of pictures of it.
http://www.detroitspeed.com/Projects...s-Am-pg-1.html
x2 on the tips being too busy. Another thought you could do is to have the tail pipes simply exit out of the diffuser with just enough sticking out to get the exhaust smell away from the car. The rest of the pipe would be hidden by the diffuser.