It really depends on your environment and the transmission type. The A-998 has to be the easiest transmission in the world despite being an automatic. I had a place to work on it too, which made this go really fast. This was a weekend at a friend's place. Got a rebuild kit for $120, undid the linkages, pan, parts, got it cleaned up, put in new gaskets and clutches and got it all back in one piece and perfectly sealed after a negligible 2 days. It was cake, no walk.
If you decide to overhaul your transmission I'm going to assume it will be MUCH easier than those 2 days simply because the AX15 is a manual gearbox. Any work between the flexplate and bell is completely foreign to me as I haven't worked with manual configurations. The parts are all available and common enough that you won't have any problems. I'm even considering a manual swap because it will be much easier to use.