It's not the exhaust that makes the power.Removing the government does.
Buy a Supertuner then find a person that knows how to use it on a dyno,you will have all the performance in the world without changing anything.With a proper tune,your 1250 will show 115 hp and around 83ft lbs of tq with a smooth throttle all the way to red line in every gear.Most of all,the surging you have @2900 rpms will completely disappear.
There are a lot of pretty lengthy threads on exhaust options for the VRSCF in the VRSCF section. Not trying to be a smirt azz but that's where they are.:hidesbeh:
But it really depends on what you want. If you like the production styling by just won't more sound and flow then go with the v-mod option. But there are some other options out there including slip ons or complete exhaust if don't you don't like the production dual configuration.