Hmmm, don't think this situation has ever happened... LOL
Actually, I'm going to make a sub forum on just that subject.
We have a few that have gone from a Wing to an ST1300, like me, then back..
If you do a search on GL1800 or Wing you might pull up some of the posts, I'll see what I can do about pulling all of them together.
Personally, I put 50k miles on an '01 GL1800 and then 39K on an '03 ST1300 before getting an '05 GL1800.. It doesn't mean the Wing is better, there are many here that have made the switch and will never be back on a wing 'til they're 90.