is it bad

is it bad to have my rear on negative cambered...... so that my rims dont rub..or what...will it eat up my tires or not as bad as having the front cambered ...hit it up...

yeah it'll eat your tires away fast.. not to mention being very unsafe, tires are meant to be used flat, not on a single tiny surface.

I would buy a camber kit then roll the arches

Well all depends, how much negative camber do you have ? Tell me how many degrees you have, you can run about -1.50 camber in the rear and not wear the tire uneven. Trust me me and all my friends never have got rear camber kits for our cars, the rear tries do wear much because all they do is go straight, the fronts wear becasue of the turning. Oh and safety isn't an issue until you beyond like -3.5 degrees. Get a good alignment and that should be all you need.