When I replaced my rear springs for new OEM units, I had to get the dealer to get the part number, the spring rate is matched to the weight of the car, this takes in to consideration things like AC etc. as previously mentioned the m-sport springs are 15mm lower than stock, my belief is that the physical springs (standard and m-sport) are a different height. You can get thicker spring pads as Rich mentioned.
Euro carparts etc. have a generic spring that will fit our cars but as with everything, you get what you pay for.
When changing my springs a few years back both front and rear with OEM springs it was not cheap, I then changed them a few months later for the Eibach springs which did lower the car a little further, to counteract this I fitted rough road spring pads, these are thicker than stock.
What ever you change to this will be better than what you have just now as your current shocks will be tired.
Euro carparts etc. have a generic spring that will fit our cars but as with everything, you get what you pay for.
When changing my springs a few years back both front and rear with OEM springs it was not cheap, I then changed them a few months later for the Eibach springs which did lower the car a little further, to counteract this I fitted rough road spring pads, these are thicker than stock.
What ever you change to this will be better than what you have just now as your current shocks will be tired.
