Welcome to the Forum. It appears that you've been doing some research already. Great! IMHO the seat you want is a Russel Day-Long which you've already mentioned. However I own a GTL which has different ergonomics, so I can't say that I have 1st hand experience what your best choice would be. I'll agree with you about the BMW OEM seat. Let's hope that some B owners will step up here and give you some 1st hand advise.