Actually, I did install them on my car, a 550 spyder.
I had a few problems, one, the bottom bush had some slag or something in it and siezed on my shock mount stud. I had to destroy the bushing to get it off (it was halfway on). Try to find spax bushes in the states
Simon said he is sending one, I hope it gets here soon... I used a spax bushing form an old mini that is close to working.
I had to use spring spacers to get my car level, as I think the springs were too short. I was able to buy std. 1 7/8th spacers from Carrera who makes roundy-roundy car shocks.
The ride seems a bit springy, I've got to fiddle with the dampening controls... The car is 1300lbs total, so I may have to go even lighter than the 125lb springs on there now. It did put the car ride height perfect, and it's a snap to change.
-DMA