I'm far from an expert on what to get/what not to get. Between the USPSA.org site and this forum you can get a wealth of info on the different USPSA divisions and also what works best for you based on equipment. I'm glad I did so because I would've ended up in Open division, getting creamed, and really not having fun had I went with my original plans.
Instead, I'm starting with a Gen4 G34 (once I can get one), no mods other than sights, shooting Production. After I do this for a good couple of years I may look into other divisions. Did you say you're already shooting Production with your XD?
Btw, my longer term goal is to shoot 3gun. Starting with Production to get minimal equipment, education on the rules, sorting out the best equipment to use, etc.