WOW, that's a nice chromed factory exhaust! But your right, it's not loud enough.
I just put an end can on my bike today. I sawed off the factory muffler and clamped on a used KERKER Supertrapp universal. Had to sort of bend a small bracket to mount it at the foot peg. Sounds much better than the factory muffler! LOUD! So far it doesn't seem that I need to re-jet my carbs.
I believe the factory pipe is 2". Go for it!