James,
It is my impression that Corbin prices don't vary much. I ordered a seat and solo backrest through Ma's last winter, at the same list as the Corbin website mentions. Bob over at Ma's was very helpful and knows his stuff. Last week I ordered a p-pad and backrest to match directly from the company. I went direct because I am getting the tall backrest (part # 225) for the sissy bar. I previously attached a 10" tall aluminum plate to the Triumph sissy bar for an extension, like Redz has. I had something specific questions on fit as this sissy bar backrest isn't a Triumph sized part for Corbin.
Solo seat backrest support? Yes, it's in contact all the time as you can adjust the height and forward/backward tilt. I ended up leaving it on all the time, but in some respects the bike's lines are nicer without it on.
Hope this helps. Ride Safe, unless it's -10F!
john
