I can underestand you wanting to go SAS depending on the type of wheeling that you do, but I sure don't understand your other choices.
1. your giving up a torquey 2.6 for a 2.2/2.4 toy motor???
2. What trans are you using?
3. Using the Mitsu. alternator (50Amp) is really the wrong way to go, whats wrong with using the toy alt?
4. "80" front axle????...thats the model that bent alot on the PU's and the front end of the Montero is heavier then the Toy PU. Why not do it once and put in the strongest front axle you can, like the '84/85' unit.
5. Most that want a SAS want it for rock crawling. Your gears are worse then a stock Montero, and with a motor that puts out less torque then a stock Montero, what exactly are you going to do with this thing when you finish it?
6. If this is a rock crawler, then tell us about the 'winch mount' up front, Its not permenant I hope.

Just my opinion, but I see this as something to do, and not something that is going to improve the rig, and to me that is not the way that I want to spend my free time.
Kary