Personally I'd start with some subtle changes until you are comfortable riding the bike. +1 on the cheap upgrade air filter. then I'd get a set of mix screws from brent to replace the "D" screws if you have them and delete the AI. All pretty simple tasks and the members here are great for advice or walkthrough tips.
Then save up for a year or two and then pick up a set of pipes and go for the air box delete and battery relocation. Then if you really want to change things up you can bob the fender for a custom look... and on from there.
Welcome to the site and I hope this helps. NR
