Hey dude,
Nice to see another gs on the board. I've my gs750, way to go is with the K&N or APE pod filters, rejet-your model probably has a dynojet kit which will take the guesswork out of rejetting. you've already got the 4-1 exhaust, maybe a shorty muffler, swap the handlebars to superbike bars-not sure how clubmans fit on the gs. I'm jealous you have the standard model, the cruiser GS's have the lame chopper style tanks and tail, which is what I've got to deal with. Your seat and subframe would look nice stock as a mild cafe.