You are going to see more than 60 psi boost if you turn the fuel up with some big injectors. I was over 60 for awhile when running the big injectors. Don't know how much cause the boost gauge only went to 60.
You will need to upgrade the lift pump set up, get bigger injectors, o-ring the head, should get studs(I'm still running the stock bolts), do some porting, upgrade the tranny(you knew that). You have to have enough fuel/air to light the big secondary turbo. Water meth will help some also if you are looking for HP. I did the cam but really didn't see a big change with it.
I have mine detuned at the moment to get some fuel economy - smaller injectors, pulled the timing back down to about 18 from 22 degrees, backed the fuel screw back out, put a stock cone in the AFC circut and set to the deepest point. Still running about 40 psi, just enough to set the second turbo off when needed. Expect some haze most of the time, at least thats one of my problems.
U-joints will need to be in good shape as well as the rear end. Also need to make sure the brakes are in good shape.