5ME runs a timing chain
5MGE runs a timing belt
5ME and early 5MGE (square TPS, vacuum advance) run the same pistons (I think )
late 5MGE (round TPS, elec advance) runs 'domed' pistons
Yup. This is just like the 18R-C -> 18R-G conversion; it's possible but you need so many parts to make it work you might as well buy a whole engine. Much easier and probably cheaper.