Hey everyone! thanks for all the kind words!
as far as modifying their was none, just bolted right up, the offsets make it perfect for our NON-M cars, M cars would need spacers in the rear. but the concavity is perfect and really looks fantastic while in motion, once i have the Z4M rotors with 135I calipers retrofitted it should look great and fill in the wheel well nicley....
you can go with a smaller tire than i did with no issue of rubbing, if you go with the 235/35/19 front then you will have slight rubbing but if you heat and move the wheel well slightly the rubbing is gone, their is no rubbing on full lock so thats great. also you may be able to run more negative camber in the front and not get any rubbing that way and not have to modify the wheel well, i still have my camber pins in.
i also lowered it on eibachs springs.
NOTE: if you run stock ride height you wont have rubbing on the front wheel wells, if you lower it you will have sight rubbing on front tire untill the wheel well is modified or more camber is introduced, and that is only if you run the 235/35/19 in the front, the taller tire is just enough to hit the front 10 oclock position of the wheel well.
other than that now that i have remidied the rubbing issue, all is good and it drives fantastic.
check your local junk yards, found these of a totalled 2011 Z4 and scored them for a real good price.
these are going on this weekend!!!!