my girlfriend's car has a perfect setup as far as toe (0 front and rear) but the rear has kind of a lot of negative camber (-2.2 degrees). I want to adjust the rear by spacing out the rear UCA at the bolts to get a little less negative camber.

my question is will making this change affect the toe in the rear?

 

yes, it will affect toe. ifyou do however change the camber, just get it re aligned.