Just want to say I am happy so far with the 17" Goodyear RFTs on my sDrive28. My regular drive was a 2006 Lexus IS250, with 18" non-RFTs, and the ride is much nicer in my X1. Even with "regular" tires, the IS 18s seemed to pick up every crack (and worse) in the road. So I am not sure the RFTs are the focus of the problem.
The X1 with 17s has less road noise than the IS with 18s too, but the X1 does have more wind noise...the H/K rides over that very nicely, tho!