If crossing at TJ, I'd recommend you park at either of the pay lots at the border (US side), cross on foot, get cards, walk back to your Sporty and the drive across. Some suggest you pull over to the declare parking area after you cross, tell them nothing to declare, but getting cards, then get the cards. I like the walk across way best. Don't forget your Mexican car insurance. I shop around, but year after year, we go through Lewis and Lewis.
It takes a village to raise an idiot.