I think the stock pipe will be more of a power limitation than a 34mm carb will be. However, a more open pipe can be excessively loud when it is making power. I did have a racebike SR500 for a season or two and it was loud and not that fast. I enjoyed it more as a street bike with a quieter pipe and better low-end torque.
I traded it for a 1976 Fiat 124 Sport Spyder. Fiat = Fix it again Tony, for every hour I drove that car I had to spend 2 hours working on it.