That's a complicated question. Your stock bike puts out roughly 95TQ at the rear wheel and about 80HP. A reasonable expectation from an exhaust change (you already have a high flow A/C) and a good tune would be 94HP/110TQ +or- 2/2 You can feel that with the seat of your pants. If you start chasing numbers, getting power in all RPM ranges, etc, it's a whole different ballgame and depends on how deep your pockets are and what you want to achieve. The stock cams pretty much die after about 4200 RPM, but pull pretty well from about 2200-4200...right where most people ride 90% of the time on a bagger. If you do a search here for "cams", "110 cams", etc. you can get all the late night reading you would ever want. And all the opinions you'd ever want to hear too.
GENERALLY speaking, it's not easy to get great numbers at both ends of the RPM spectrum. It can be done, but it's not inexpensive to do so. There are a few "bolt in" cams that can certainly improve things a bit without going nuts chasing big numbers.