If simply gaining more horsepower were the goal, we all made a poor investment buying our 790cc parallel twin. Good gravy, all one would've had to do is, for about the same price, buy a Speed Triple. That would've accomplish 128bhp being stock as a rock.
Nevertheless, I may at some point install a big bore kit. Especially when I start adding up the miles and I'd want to replace my piston rings anyway. I would, however, opt for that kit that comes with a "Nickelsil" coating (which is offered as a complete bolt-on kit at
http://www.danddcycles.com/ ).
-BT