Just in case anyone else is looking for info on this with SPD. I talked to one of they guys there, was super helpful actually, so it might have just been good timing. He's actually done an install on an Expy so had some tips.
First, for the turbo adapters, he recommends a torque setting on the studs to be 45 lb/ft but make sure you use a lubricant like the Ford anti-seize or something equivalent.
Second, for the downpipes. They don't list Torque settings for the clamps because there are too many variables, i.e. how far tubes are in each other, rotation, etc. They recommend tightening them until the bolts "stop" apparently they are specially tapered or something that clamps down well. Recommended that you start the rig and get under it to check for any obvious leaks. If you find one, try tightening a little more, if it doesn't go away, try rotating the clamp a bit, then retighten. As for install, he said you should start with the drivers pipe, do the passenger, leaving all nuts partially tightened, then the connecting tube and finally the one to the muffler. The tighten everything. And finally, after about 40-50 miles do the retighten.
Really want to do this asap, but I'm dealing with the turbo replacement issues right now.