I've been tracking alternate exhaust systems for a while and may do something this summer. If you don't want to spend a ton, like on a Akrapovic, or middle of the road, say Yoshimura, Arrow or Leo V, or spend a bunch and need to re-map, like with a Two Bros, look at the Delkelvics.
Actually, after hanging with people with a myriad of pipes on their bikes, our stock pipes really don't sound that bad. They just weigh a lot, but with the location, it's no real issue, IMHO. Has anyone with the much lighter exhausts realized better performance?
2009 Versys (Mine's Green)