I have a few thoughts right now.
Option #1
Mount up my R888's on my current rims and do it all like I orginally intended when I bought these wheels. By all I mean, autocross, road race, and street. Also being able to drive to the track. Run exibition if I must and be able to do it all reasonably well. Clearly the most economical since I have the wheels and tires already.
Option #2
Buy another set of rims 18" rims (Likely my street rims) and mount my current KDW's. Then mount my R888's on my current rims OR put a set of A6's on them and trailer to the track. My only hold back here is the difference between R888's and street tread isn't HUGE.
Option #3
Go to a Vintage Wheel Works 17" wheel for race. 17x11 and 17x9.5. Then I can run Kuhmo V700's, R888's, or A6's easily. They are inexpensive and you can get custom backspacing. I can buy rims and tires for just North of $2k.
Since the upcoming Super Chevy show is 100 treads. I'll likely start with option 1 and take it from there. I'd like to stay with the same widths so my alignment doesn't change between wheels.
Option #4 (Shameless) If any of our site sponsors would like to throw a set of wheels my way. I'm sure my 210,000 view thread, event performances, and general post whoring duties could benefit your business multiple times over the cost of the wheels.