When you say "slicks", are you really referring to true slicks, like the Yokohama A005? Or are you talking about R compound track tires with at least a minimum of tread, like the Yokohama A032R and A048, Hoosier R3S05, Toyo RA-1, etc?
And, while there are "ideal" sizes, you will need to stick to what's available, and what will fit on the stock size wheels (17x7 and 17x9). Some people use oversized tires but they only fit on aftermarket wheels. You can't get much wider than the stock sizes (215/40-17 and 255/40-17) on the stock wheels. Given that, the stock tire sizes would be a good bet, if they're available (which for many track tires, they're not).
If it were my car, I'd get the Toyo RA-1 R compound tire, which comes in 205/40-17 front and 255/40-17 rear.