suggestion that you get all the parts you need BEFORE people show up.
You need new crush washers for the oil fittings, new gaskets for the return line, one turbo bolt, because the stud sucks and it should be removed and replaced with a bolt. If you do that, you never have to take the manifold off again.
you need jackstands and a jack to get it up good and high in the front for access from below.
You don't really need a torque wrench, but it wouldn't be a bad idea for the turbo to manifold bolts.
Just to reiterate, this is a good idea. I think you will also need new crush washers for the coolant lines. Will the oil feed line from his T25 (i'm assuming it's stock) work for the 16g? If not you could just get a nice SS oil feed line with 4micron filter in-line. Quick trip to Kinetics would set that up. Or find a stock 14b oil feed line, i think that would work.
You need 4 manifold TO turbo bolts, not 4 manifold and turbo bolts. They're long (70-75mm i believe off the top of my head? could be wrong) but you could re-use 3 of them and just replace 1. This could also be done when the manifold bolts are out and you bribe someone to drive you to lordco or home depot while it's out to match the length and pitch. (i want to say m8 X 125 but can't recall, been so long..)
What are the chances that the manifold bolts will come off nicely? Probably going to pull some studs out for sure, hopefully not snap any of them in the head. I'd use a hearty amount of liquid wrench on those bolts, perhaps even the night before to let them soak. Those bolts snap and you've got a headache.
Will the intake that you have work for both the t-25 and the 16g? I seem to remember that the t-25 has a smaller inlet? (2"?) whereas the 16g i think is 2.25"??
Food for thought, all rights reserved, all wrongs reserved too.