It will run OK with the stock jets, and you can slowly up-jet one step at a time after you've got it running. For example, if the main jet is a 95, step up to a 97, and then 100. Don't jump up too many sizes. The stock jet will be fairly close. Then you can do the same with the pilot (idle) jet. Don't change both jets at the same time.
Yes you can install the BBK without removing the engine. You just need to remove all the plastic fairings near the front of the engine, and the exhaust system. You might want to install a race cam while everything's apart. They make a noticeable difference in power. Only about $30. There's some excellent YouTube videos that will show you how to do it.
