go talk to blair and craig at Adelaide Bike Works on south road .... great blokes and Craig awesome engine builder .... and ride sounds good ... maybe PM me when you dont have kids and we meet for a BLAST

Scouser, have a read through this: http://www.sportster.org/tech/typical-staged-sportster-engine-upgrades/

It isn't a bible by any means but gives you a rough idea of some of the stage upgrades you can complete and an indication of HP

Alternatively, have a look on this site xlforum.net, its got massive amounts of info from XL fanatics all over the world who have invested big bucks to get 100+ hp out of a Sportster