Olli, thanks for the tips. I'll research the RS3.6 crank. I'm just not sure how readily available those are. 993 cranks come up from time to time on EBay, so those are easier to source
As for the titanium retainers, everyone uses those and I guess if the car was going to see lots of track time, you might as well have that extra insurance. For a daily street motor, it's not worth it I'd say.
TimT, that is an awesome setup you have there! The problem I have with rear mounted turbos is placement of mufflers. We have very strict EPA laws down here and I need a properly muffled system. If the turbo's were mounted to the side of the motor (near #1 and #4 cylinders), I could use one of those oval Magaflow dual in/out muffler cans for ease.
I wonder if there are any NA headers with the collectors just before #1 and #4 cyl's?