Has anyone lowered just the rear wheels?
 

I just put on some new wheels, and was torn on installing some Eibach Proline lowering springs. The front wheel gap is less that the back wheels. Has anyone lowered just the rears to even it out?

I can't say it hasn't been done but I have never seen it.
Think it would look pretty silly actually and would probably mess with the handling as well.

Ok well since you just put the new wheels on I would give your car a day for the suspense to resettle after jacking it up before you look at the wheel gap. And lowering the rear only can lead to a boat like look (ever see those cars were the rear suspense collapsed). If the gap is less in front I would try spacers in the rear that might make the gap look smaller.