The 22RE is one of the best engines Toyota has ever made. It only has one real weakness - the timing chain guides were made of plastic and after 100,000 miles or so they frequently become brittle and break, which leaves enough slack in the timing chain for it to eventually saw through the timing chest into a coolant gallery. The permanent fix is to replace them with (lifetime warranty) metal timing chain guides from DOA Racing Engines:
http://www.doaracingengines.com/page13/page13.html In any event, if you don't know for sure that the guides have been replaced, now would be the time to R&R with a full timing set before you go to Mexico.