It doesn't have to be either.
I've done it with other cars that were (a) not AWD and (b) not mine.
For AWD cars, I'd do it on your gearbox -- but not mine.
Ford actually put out a manual for their MS90 gearbox and it was covered. However, if you have an MS90 you are not hurting for money, and you don't have just one -- you have enough spares to build a car from scratch typically. Oh, and an MS90 used to cost as much as a road going version of the entire car...
So yes you can do it. It'll get expensive sooner or later and if you are not good at syncing it'll be sooner rather than later.
What's the big hurry to shift anyway? It's pointless.