Put one on my '05 and have about 3000 miles with one on my '08 as well. No problems with either. I recommend the Wingsoft and Utopia backrest as well.
I've got bad back/hip and almost went with a Russel Daylong. I had a Russell on my FJR and was very happy with it.
The Reason I didn't go with the Russel was I wasn't sure about the little notch that is cutout where the backrest goes:
And the Wingsoft/Utopia looks better:
I figured I'd spend $400 on the Wingsoft and Utopia and if I didn't like it I'd go with the Ultimate with backrest (Looks good but not sure about function).
I also asked John about seat density/firmness, if they were all the same and he said the firmness can/does vary according to where a particular piece was cut (from the main sheet of foam).
I told him I'd like to have the firmest piece he had. I noticed immediately riding home that I could see over the windscreen with the screen all the way down when before the top of the windscreen was in my line of sight.
After 3000 miles I'm still looking over the top of the screen so the foam has not sunk any but has got more comfortable (less hard and less feeling like I'm sitting on a bubble).
I hope this makes since and may be of help to others.
I am not able to sit on ANY stock seat for more than 10 minutes.
Give the Wingsoft a try, if it doesn't work get a Russell.
Steve