most of the time ppl remove the fronts due to the front sitting alittle high... which is common with the eibach sportline springs...although removing them really doesnt help much...u might get 1/4" if ur lucky...
This is why.. IF you don't wrap it in tape it will make a little bit of noise. wrap it in duct tape and you'll have NO noise to speak of.
The second reason, if you have real short springs, the spring will fall out of the control arm with out the isolators, this won't happen unless you cut the spring, but with out the iso it will still be very loose until the car is lowered and you must make sure of the orientation of the spring right before you completley lower the car.
Thirdly, it's not as big a diffrence in drop as it is in the front. it's more of a 1/4" drop or so.