Wheels for slicks?

What is the cheapest way to get a set of wheels for slicks?
Can you get a 15" steel wheel to fit the Cobra as a direct bolt on?

If so what are the specs?

If not what is the cheapest aluminum 16 that will fit?

I donlt really care what they look like as they are for the track only. I would prefer 15" steel x 8" wide.
 
Also, I e-mailed Bogart and here was their reply:

Yes you can run a 15x10 with a 6 1/2 backspace from what I hear it should not hit the cobra calipers on the rear. We do have a street strip wheel but I dont think it will clear the calipers only the drag wheel. You will need a open end mag lug nut not uncommon to find them in a parts store. A 15x10 will run you $356 each and will take about 3-4 weeks to complete.