Hi Steve, I have been doing some research on exhaust systems for my track car. I have a '71 than I am putting a stock '83 L28 into. Have had the intake ported and polished, but that about it, so far. This car will be used for NASA HPDE's, open track days, High Speed AX and still has to be civilized enough for the street (no trailer, have to drive to the track). So far I have bought a Pacesetter Header with Jet Hot coating. My initial plan was to go with 2 1/2" pipes and end in a turbo muffler. Saw you post and found it intriguing about the tuneability of a Supertrapp. Did you get to the dyno? I would love to hear your results. From the date of this post, you must have some experience with the system by now. What do you think of it? Thanks, Marty