[Mr.ac]

If your only going to do a track even once. Go as is. Just make sure your cat is in perfect running condition.
If you plan to run more than 3 times a year, I highly recommend getting a second set of wheels with sticky tires, better brake pads, a good tire pressure gauge not those $2 stick ones) and some 2x4s just so you won't use the parking brake after a hot lap. (That's how lots of people warp or explode their pads.)
Other than that just go out have fun. But more stuff if you want to. I'll rather spend more for track entry fees