The back will normally sit higher than the front anyway. This is due to the fact that there is a greater amount of travel in the rears. The weight over the front wheels is pretty much a constant (weight of driver and front passenger is roughly spread between the two). The rear springs have to allow for more travel due to the weight of rear passengers and anything in the boot as this is all over the rear axle.
Attached is a pic of mine lowered on 35s, the rear does sit higher. Yes that is a little bit of paint on the rear tyre lol.