I use Black Magic on my cars, too -- but I spray it on a spnge, and wipe the tires with the sponge. This way, it applies the stuff, but it also spreads it evenly, and wipes away the excess. Sometimes I'll re-wipe them later, using the same sponge, but without re-applying any dressing to it (so the sponge is just kind of moist). Seems to work well, though I haven't used any on my MY Z06 yet.
-Kirk
------------------
2001 Z06
MY w/Black
Memory, Mirrors, Mats, and Moldings!