Lowering the rear will increase negative camber. With proper adjustments, you should be able to get at least 2.5deg rear camber which is probably too much for a street car.
Here is an article with some how-to. I have my rear camber set to -1.75 deg which is an in-betweener as I am looking for decent performance in Autocross. I have front camber at .75 deg but I lower the front for AX which temporarily increases neg camber a bit.