What XJ Engine Mods for Mexico??????

I just bought a 1990 XJ to take down to Mexico and leave it at my RV site where I spend the winter. Because the XJ will not be used in the States and the state where it will be licenced does not require any inspections, I was wondering what I could do to clean up all the spaghetti under the hood. I am constantly getting vacuum leaks in my other XJ and I am sure some of the smog stuff is robbing power and gas mileage. Where would I look for information on what the '90 XJ engine can do without and be the better for it?