here they are
http://www.ebay.co.uk/itm/3716737268...%3AMEBIDX%3AIT
You'd still need the fronts to match, think I paid £180 new from BMW for them.
If it's a road car if I were you i'd be more inclined to go for a new Eibach kit; i'm sure you'd be happy with the handling improvement and increased comfort for the expenditure, even better if you can get a decent kit second hand.