I'd recommend staying on street tires, too. This is my 2nd season on street tires, and I'm contemplating a 3rd- I'm pretty sure I have the skill to move up and be competitive in open class, but I'm still learning and just too inconsistent.

There are different levels of r-comps; competition tires are the fastest, but wear extremely quickly, too. R-comps that last a bit longer are a bit slower, too. A good set of very-high end street tires (Star Specs, RE-11, Ecsta MX) are not far removed from average r-comps and will take much more abuse, while still providing more warning on the edge while you learn. If your r-comps are old and hard, there may not be any difference at all.

Plus, you don't have to worry about changing wheels The local street tire classes are pretty competitive, so you'll still have fun.