Thanks guys! I went ahead and got my 3rd member off, rusty studs holding it nice and tight. But I got it off without marking up the housing bad and yeah the new 3rd member fits right in and the driveshaft bolts up. Should be wrapping this up with a test drive in an hour or so.
Oh yeah that's right, the fancy R200 pathy stuff, they don't seem tooooo bad to take out, I did find a couple pre-facelift pathys with the 4.6 gears so that will be the next mission. And also while my truck is tucked in the backyard I'm gonna be doing more rust repair, fun stuff, I'll have to update my build thread soon.