Mike, you might want to reconsider the T5. Its an ok transmission (I have it) and has good gear ranges. I am assuming that you have the Dana 300 transfer case....Hence, it should be a straight swap on the tranny....however, adding the shifter and clutch is another matter. It will be quite a bit of work to get the clutch peddle in. You will also have to install a new flywheel.
Going from an auto to manual is a lot more work than the other direction. Personally, I would keep the auto...in fact, I plan to swap out my T5 with a GM 700R in the near future. That tranny has a great 1st gear and overdrive. Built properly, its as tough as the old TH400. The only expense besides the tranny would be the adapter for the bellhousing and transfer case. I belive its about $450 from Advance Adapters....but don't quote me on it.
Oh...one other thing....before you go to a manual, drive one with a stick on the trails and see if you like it. I have a feeling you will prefer the auto.
Let us know what you decide.
John......southern CA
84CJ7, 3"lift, 32"BFG, 4.10's, ARB Locker, Solid Axle's, Durabak