As for the tires, yeah, there are some track tires available in 15" that will work, but not even all of the autoX and road course classes allow them. Most of the popular classes that are fairly easy for the beginner/layperson to do, like CAM or even Optima, limit you to a 200 treadwear tire. So, it has to be a street tire, not just technically DOT legal. Most of the track tires are rated 100 or below for treadwear.