Wow! That does sound interesting. Sounds like a pretty deep mod. It’s going to reduce the torque quite a bit, but since the GT has plenty, that shouldn’t be so bad.
I’d be concerned about how the overall geometry changes when making a wheel and swingarm change like that. It could be more stable at speed or less, partly depending on how the rear ride height comes out.
Back to the subject of tail light. Part of the reason it’s so dark is the tinted lens on the back. It would be great if they came out with a less-tinted version.