Like he says in his description , be careful with the spigot (bearing housing) size on the rears. With this particular design of hub centric spacer you'll encounter the problem of the counterbore on the rear of the spacer being too shallow. You'll probably find that from 15mm up you'll be ok as this allows more depth on said counterbore. There's plenty on here who have 10mm on the rear but they must be the other design. I'm sure someone will put a pick up.
These are ok on the 4wd stuff though ( r32, s3).
Chris.