Lowered my 2001 wrx yesterday, just front and rear springs... tho now when drive over bumps/speed humps/grids etc i get a knocking noise from the back, sounds mostly from n/s/r but o/s also. there isnt certain ways of fitting the rear springs or struts is there? or anything have to be modified when lowereing>?

pleae help as its anoying and also dont no if its damaging anythin? cheers

oh ye its only done this since fitting the springs