Was originally going to buy the real things...until I found out that they aren't all that light(apparently that's the case for almost all BBS wheels). i.e. the difference between the real ones and these is less than 2 pounds.
For example, in 18x8.5 the real BBS LM are 22.4 pounds, while the reps are 24 pounds. So a difference of 1.6 pounds, for an extra $3-4K. Granted the real ones should be a lot stronger...but def not worth it on a road car unless you have money to burn.
The set I got is 18x8 on the front and 18x9 on the rear. Offset is +35...which was a cause for concern since I searched the forum on whether or not +35 offset fits the non-m Z4 and half the posts said yes, and the other half said no. Well in this case, they fit very well, with absolutely no rubbing front or rear. Granted I'm on stock height, but that had me worried for a moment.
For tires I wanted to ditch the run flats, so the wheels have Michelin Pilot Super Sports mounted(225/40/18 in the front and 245/35/18 in the rear). In the end of the day I ended up saving an extra 5 pounds per corner by ditching the runflats.
So overall, the reps + michelins ended up being 3 pounds lighter compared to the real BBS with run flats. So it's not that bad.
The Super Sports are a huge improvement compared to the runflats, car is a lot more planted(don't feel every bump), has a ton more grip and doesn't seem so loud at highway speeds. I can see why it's ranked #1 in it's category.