As above, I would assume in theory they should be compatible, however any issues foreseen?

thank you for assistance.

 

I'm pretty certain different length springs are used as different strut design,
I've got an 05 and the front & rear shockers are inverted like on STi, pretty sure 2004 earlier they were not & is also the reason you won't find after market shocks for 2005 onwards WRX range(excluding coilover kits from that statement) Initially i didn't realize the stock shockers were inverted etc. and so was looking to upgrade but found all makers Kyb, spax etc. ended their listings at 2004

 

Springs are pretty much the same length but the shape of the rear springs is completely different starting after the buq-eye. Front spring shapes are all the same and are interchangeable. The rear strut top also changed to accommodate the new spring shape.