If you have $, anything is possible.
But being realistic, no.
mx6 is FWD, rx7 is RWD. there's already that problem to start with.
then you gotta do some major internal work to get it fit inside the hood of mx6 then worry more about the rwd conversion or something else to make it work.
goto mx6.com. they have great info on the cars and they will help you alot on any questions.