Would the Hoosier R-compounds work for drag racing? These are the only R tires I could find in 245/35/18.

What would work better, AS303 or RS303?

http://www.tirerack.com/tires/images/hoosier/hoosier_a3s03.jpg

Could they work better than your average street tire? Sure. Will they be as effective as drag radials or ET Streets? Not really.

The tough part, also, is the 18" size with only 35 series sidewall.

You need as much sidewall as you can get, and the softer the sidewall the better, for flex.

If I could find a 15" wheel that would fit over my rear brakes I'd do it in a heart beat for drag racing so I could get a decent sized sidewall for some real flex.

As it is with my 275/40-17 drag radial's with low psi (16-18 psi) I can get some sidewall flex and avoid cupping, all of which help with my launch and short times.

Drag racing is a completely different animal from auto-x and road courses, when it comes to tires. You want smaller wheels (diameter), taller tires, lower psi in the rears and higher psi in the front (for less rolling resistance).

My recommendation? Get a cheap set of rear wheels that are light weight, go as small as you can to fit over your rear brakes and get yourself a set of drag radials or ET Streets (if you go small enough for them), mount the tires up on the wheels and keep them in your garage, and simply swap on the wheels/tires combo whenever you plan to go drag racing, and swap them off for the rest of the time and ride around on the street on your 18"ers...