Can you tell me the model no of the cars eg ae????what are they both the same type eg sedan /hatch
as far as im aware they are the same fit but you will have to make sure the spring rate is the same or close try rining a specilist and ask if the spings from a lift back are the same as a sedan hatch ect if so sweet>>
Things to check
a. diamiter of coil the whole lot not the actual wire thickness
b. distace between bottom and top of spring compressed in each car
eg if yours is lowerd add a bit to the mesurment say 2 inch and if its close to the same distace on your mates car sweet no probs