Yeah, he wanted to run on the highway because at 50mph in a low enough gear he'd be running pretty much full boost with no lag. if it wasn't an AWD model, he wouldn't stand a chance in a light to light race, they just don't have it from a standstill. Now, I did test drive a '95 AWD turbo Eclipse, and so I can say from experience that they can be launched at 6000rpm no problem- and I do mean launched. I thought the salesman was going to faint, it was great. I pounded the crap outa that car, and he was right- it really was fast! The point is, they aren't to be messed with in a stock 5.0. However, I think you obviously had this one in the bag. I'd start with gears- a well driven bolt on stang with gears can take even a fairly modified DSM, AWD turbo or no. Running a blower yourself would fairly guarantee you a win, but not if you can't make it stick. You shouldn't have to resort to boost to beat this guy, or any of his gangbanging buddies.
*edit: yes, 58cc chambers are going to make for higher compression than is preferred with a supercharger- not that it hasn't been done successfully by dozens of people. Just riskier.