I saw a post on another RT site about spark plugs so decided to check mine before the 24k service.
At the 12k service the plugs, compared with new ones looked fine.
This morning, at 21,728 I decided to take another look before the garage goes into Texas summer August nuclear conditions....
The right side still looked good:
The left side however did show some wear.
BMW advises the plugs replaced every 12k which seems like a bit much to me, none of my previous bikes ever needed replacements at that interval and definitely never showed that kind of wear.
But, I guess BMW knows something so I'll be replacing at those intervals moving forward.
As for performance, the bike hasn't felt any different between now or when on day one or it was such a slow difference I may not notice 'til my next ride on the RT.
Just throwing that out there for other RT/GS owners.