I second RENTING! While I've never even been to a Baja Race, I have been around racing for a while. I used to work for an SCCA Road Race team and we built cars and sold them and offered full support to their owners if they needed. We had a couple "house" cars that we built and we'd rent them out for track weekends (and driver's schools) to people who were just getting into the sport, or couldn't afford to buy a car and run it on their own, let alone fully supporting them.
The experience the Renters got from just flying into the local airport and showing up at the track and having the "team" do all the prep work on the car; let them focus solely on their driving. Guys who do it all themselves don't always get to race. If the car broke in practice or qual they were the ones that had to fix it and if they didn't have spares the car was going back home without ever being raced. You just blew your whole weekend and spent a shitload of money.
One of our "Drivers" was even an ex-SCORE Buggy Racer (Little buggy w/4cyl toyota engine) who tried doing it all between himself and a partner. I think it burned him out trying to manage everything on his own, it was much easier (and less stressful) to pay the money and show up.
Here's to seeing your Baja Dream come true