Check it out - it's fairly easy to switch. It's also fairly expensive. What would be the easiest is to find a wrecked MX6 manual, and buy the tranny out of it. You won't be able to find out what kind of condition it's in because you won't be able to drive it, but I would go ahead and inspect the synchros before installing it in to the car. Basically - you need the transmission, possibly the half shafts, shift linkage, shifter, and shift mount. Everything else will be the same. Good Luck!
-Cody