x2 depends on the condition of the gasket. Mine did't tear but i used some gasket sealer when i put it back together. If it tears you may want to get a new one. It is better than haveing to do it all over again.
If you put a little oil (just a very light film) on the gasket before you install it, it should help keep it from tearing next time you pull the cover off. Don't do without it though, you need it to provide clearance.
Heard of 'um, but never used them. When I split the case, part of my rebuild of course is cleaning the mating surface of old RTV. When puting back together, I use a bead of RTV, vs. an actual factory gasket. Been thru several DD's (isnt that right bggreen) but not traced back to a bad gasket.