Re: swapping force to a e-tec
BRP, the maker of E-Tecs has been around and been making power products for many years. E-Tecs were first introduced ~2003 in the big block V6's, then the 3 cylinder motors and then the small block V6's (150-175-200).
This has been a very successful motor line (I have owned two 175's since 2007) and most have been trouble free. If you get one, use XD100 oil only.
"Switchover" involves all new engine controls, an oil tank, etc. Any BRP dealer can fill in the details for you. None of your Force stuff would be reused, except maybe the tach.