I have 20mm front and back but not with OE wheels. Handling is fine and no vibes.
Not had the car lowered yet but it shouldn't be a problem.
 
where were you thinking of getting them from mate?

Id quite like 20mm front and rear.....will you need longer bolts too????
 
i wouldnt mind maybe spacing each corner 5/10, but you cant get hubcentric for this so its not worth it for me
 
for the hassle of longer bolts and then new locking wheel nuts (if you can get longer ones) its just worth the fuss really.
:-(
 
i want spacers so i can fit bmw rims. anyone knows about this?