When I bought my 1150 I was told if I wanted to fit the Avd hard luggage that I'd need to swap the rear subframe and seat too.I suppose the same would apply if you wanted to swap the seats in the other direction, as the sub frames are apparently different.As Alex said, if you could find someone who wanted to swap, or even a standard GS to park besides whilst you kicked tyres over a couple of beers it should resolve any differences and similarities.