Just an opinion here to throw in the mix for folks that are considering bags.
The BMW bags are a crap design at best. They must have contracted it to some outside firm that has never seen any other bag offerings.
The tank bag leaks like a fishing net btw. And it's an ugly pos. The bmw tank bag, mounting bracket on the other hand is a nice design. Wish i'd waited an extra day and got the info for the bracket, then ordered a nice sw motech bag to mount on it.
Hepco becker makes a very nice base plate that locks on the tail in place of the rear seat. It allows you to mount pretty much any tail bag on the market without damaging your paint. Hepco also has some nice saddle bags, too.
Love my blaze side bags, for looks good storage space, and once removed, bike looks stock again. I have the brocks exhaust and have no issues.