I'm looking at swapping my 27" Q2XL cam for a 29" cam. It worked out that a guy was looking for a 27"er and I was looking for a 28.5 or 29"er. We probably will just directly swap cams.
Now, should we swap strings and cables as well? I would guess yes, but I'm not 100% sure. Even if his string isn't in the best of shape, it could be used as a backup for some outings. Same with the cable.

Thanks again!