You don't say what year bike you have, but the 15 & 16 models are already 1" lower in the rear. I think if you go any lower than that, you are going to have handling issues unless you lower the front as well, & it's probably gonna ride rough if you only drop the rear, say 2" or so. Although 2" doesn't seem like much, it is when it comes to suspension.
Lil Chief
Lil Chief