I've never crossed at Otay. I always used to cross at Tecate because they didn't even check registrations, then going down for the 2015 1000 they wouldn't let me in because I had so many spare wheels and tires. The inspector told me that they had a new guy in charge and everything was by the book now. I believe he said 2 spares per vehicle (I had 2 quads and about 10 tires). I couldn't even pay the duty as the official who collects them was off (it was Sunday). Drove to San Ysidro, no problem, just checked the registrations. Same thing crossing for NORRA last year (with a buggy on a trailer) and for the 1000 (2 quads on a trailer with multiple spares), just registration check. If you do cross at San Ysidro, right after the inspection area you can pull over to the right and get your tourist cards if needed-fast, easy, free, and plenty of parking.