I bought Skunk2 coilovers but am only going to lower it about 1-2 inches. How much will that effect tire wear? Do I really need to buy a camber kit?

With a 1-2" drop not really. What you should do is make sure you correct the toe after your drop and if you can ask for 0 toe front and rear. Toe I believe affects tire wear quicker than camber.

Since there is NO camber adjustmend, a camber kit really should be used with .25" drop. From my past exp. I'd say you only get extreme negative camber when dropping 2" or more.

Toe out on the rear will make it tail happy - not for street use.