I am going to have to put my $.02 in here. I think that DavidZ would run very well in SM. Heck, with all the mods, you'll run well in just about any street car class. This sport is not about winning or losing. This is about gleaning all kinds of enjoyment out of driving your car right on the limit of adhesion, honing your driving skills, meeting and BSing with others of like mind, and checking out all the other great enthusiast cars that are there at the event. The reason people don't protest is that there is an unspoken gentleman's code out there among racers. I doubt anyone would protest DavidZ in STS, but I think it'd be obvious to a few that he was running a LSD. He might get approached by a couple of folks and asked whether or not he has read the rules, but probably not much more than that. This is all about you and your car and the track vs. the clock. You beating your own time. Believe me when I say that you'll have a great time regardless of what class you are in or whether you win or lose. My suggestion is that you get a set of race rubber and go out there and try to have the most fun you can have on four wheels. In the awesome car you have made, it shouldn't be a monumnetal task. Go street mod. Sure, you might lose...but you might win. Either way, I am sure you will really turn a few heads with quick lap times. Sorry for the rant. I haven't/won't ever cheat in the SCCA. I believe in the code. When I win, it will be because I am the better driver, not because I have undermined the rules of the game.