Don't get me wrong, I do agree with you for the most part. A turbo is more efficient, has higher power capacity, and is not limited by engine speed, and in most cases is preferrable to a supercharger, I completely agree. However, turbos do restrict exhaust, and it is not free horsepower. Sure, the flow is nice at your muffler, but that is after the fact, the restrction is the turbo, once past that it should flow quite well. The turbo has to be a restriction, othewise the turbo wouldn't move, as they are driven by the pressure differential (or temperature differential, but that's just splitting hairs really). Just think, that's why you put the best flowing exhaust on after the turbo, to maximize the turbo pressure differential. Yes, they make up for the restriction certainly, but they do restrict exhaust and thus cause a loss in power. Takes power to make power, there is no such thing as "free" energy.

I don't claim to know much about autocross, that comment was from a friend of mine. He autocrosses quite a bit, and has repeatedly seen that sc are easier to use (although I guess not necessarily better?) on a course than a turbo. I have no idea if it changes classes or not, but I would assume a non-factory turbo would as well, correct? I had made the comment more in the turbo vs. supercharger idea of the thread, but if it's better to stay NA, which what I assume your suggesting, by all means do that.