I emailed hammer and asked this: "I have a 2003 buell xb9s with 6000 miles. I have been looking to put the big bore kit in the bike, and while I'm there, I might as well have my heads done. I am looking to just tear down, and bolt on these upgrades without machining on my end. What are your thoughts and do you offer everything I am asking?"
This is what they said: "The bolt-on kit for your bike is commonly referred to as the "1050 kit", but in reality it's 1021cc (hey, I didn't come up with the name!). It represents just under 4% more displacement than your stock 984cc, and to the extent displacement constrains power (and it does on your motor), that means 4% more power. In reality though the power gain generally comes out more on the order of 5-7% as there's an increase in compression that comes with it, and also the larger bore slightly unshrouds the valves on the short side, improving flow. The 1050 kit sells for $699.95.
The next step up from there involves a full tear down. With a tear down, you can do a 3-13/16 bore (1170cc) or an XB12 crank (1203cc) or both (1426cc). Going to the 3-13/16 bore requires that you send your cases to us for boring.
In addition to the above, consider head work as well. With the stock 3.125 stroke, the XB9 is not a terribly undervalved motor like so many of the other XL/Buell models, and as such, honestly, it does not benefit from head work to nearly the same extent. But it does benefit from some port work and a good valve job. I would recommend the "Impact" level ($550), which with the stock cams, should be good for another 5hp or so.
The XB9 is a bit unique, to be honest, in that it's already a pretty well tuned motor even in stock form. So the bolt-on path is nothing earth shattering, like the 50%+ gains we routinely pull out of XL1200's for example. To get gains like that from the XB9 you need to go big with the full tear-down options.
We can provide most any or all parts and services you would need for the project, no worries there. Let me know a little more about your goals and budget and I'd be happy to make a more specific proposal and even generate an estimate.
Thanks"
So basically, 1050cc kit is $700 and heads are $550, and with the gaskets and other misc stuff, you can probably get about a 10% increase in performance for ~$1500.
