Definitely with IJ on this...BUT if you want a nice Scca/Auto-X car, N/A is better in my opinion because of the smoother power feeling and responsiveness. Especially if you have a hard top, they're lighter than the Targa's. ;] I beat my friend's turbo at Scca all the time, he NEVER beat me. I had blown suspension, open dif, free used street radials and no shift bushings.... BUT in the straight line he would always win. LOL It really just depends on what you want to do with it.
If you want SCCA, a set of coil-overs dialed in, Racing seats, nice set of wheels and good tires, LSD, a fresh rebuild and a good exhaust with not cat.... You'll be pretty set ;] And if you're feeling frisky you could bump the ignition timing up to 14 Degree's and run 93. And you could drop some more weight, carbon fiber hood, etc. I got my white supra down to 3100 pounds. I think every 100 pounds you drop, is the equivalent of adding 10 HP if you kept the weight. But that's me, take it with a grain of salt ;]