I was looking at my car this morning, and noticed the front arch has loads of clearance compared to the rear. I have gotten lowered springs to lower the car by 40mm, but now am wondering should I just lower the front as the rear looks pretty low at the moment and I don't exactly have a tonne of weight in the boot. (or could my stock rear suspension be low already, as in deformed low?)

Any Ideas?

fit all 4 springs,could be your rear springs are sagging a bit. if thats the case you will benifit from the new springs anyway