i bought a milltek with the hopes that it'd fit my post-facelift z4. at the time, nobody could confirm so i was the first guinea pig. long story short it does NOT fit post-facelift models. the piping diamter, overall outlay, etc are all different. i did choose milltek b/c i had great success with them on my vw and they consistently get great reviews from audi guys. i did notice though that even w/o putting on the system i could tell it was going to be loud due to their straight pipe design so you may experience drone.
i ultimately with with bastuck. they were the only manufacturer had a fitment for the post-facelift. i believe supersprint may now offer something but back then they were only offering 1 system which fit very poorly since it was really meant for the pre-facelift.
