For auto-x, you'll need to pay attention to the class you plan on running to determine if the slotted rotors are legal. It is very possible that a seemingly "innocent" upgrade will move you into a class that is less than favorable for your car. But, if you aren't concerned about being the top of the class, then all of the last paragraph is moot.

I haven't ever heard anything regarding ceramic pads not grabbing right. All brake pads have different initial bite and friction characteristics. Any performance pad, though, will likely create a bit of dust and possibly squeal like hell. A number of the CSCC guys have used Carbotechs and liked them.

Also, slotted rotors would cause your pads to wear more quickly. Think about it like this, if you were to rub your hand across the face of the slotted rotor, you're going to feel the grooves, right? Well, the brake pad friction surface will "feel" the same grooves. Those grooves are going to act kind of like scrapers with each pass over the swept area of the brake pad.

Slotted rotors on a street car are, imo, overkill. You don't really need them in daily driving, or even for autocross. A high quality brake pad and fluid will be plenty for both.