unfortunately it varies by the year of your car, as there have been issues from 03/04-05/06 and not sure after that? if you had an early model, i think worst case would be washers as the brackets seems to be a tad bigger?
no straight answer unfortunately. you could remove your mount and measure the rear section (chassis side) as that's the been the issue. see if the guys over at SU can help you from there.
i have a AWR MS6 rear mount on my 05 6i. the mount was slightly wider then where it mounted to my chassis. but that part is also like 4 layers thick of steel. so i literally just peeled a layer away so it was just slightly wider, and the mount went right in.