I run Bilstein Coilovers all round.
NO modifications are needed for either front or rear as these have been developed and are manufactured by us to fit. The only bit we import is the Bilstein insert from Germany.
Priced at £250 each or £995 for the full set. (For 4 Leda's I believe your looking at around £1400)
Depends on what you are going to do with the car at the end of the day as to what sort of quality and price you want to pay.
Tony