Whoa! twins will be a neat trick, where you gonna put them? Not much room in there. Definitely would like to see pictures. I'm sure the crowd on TDICLUB.com would definitely like to see the project in progress...
What do you hope to gain from twins vs a single GT-20 or vnt-17 turbo, for instance? Guys in Europe are putting down deep into the 200's hp-wise with a single Gt-20 or -22 turbo, or a vnt-20. How are you going to keep the ECU happy? There's a 3-bar MAP sensor that can get you to 29 psi with proper reflash, stock one is limited to 22 psi.
Power is ultimately limited by timing. 24 degrees crank (12 degrees cam) is all she'll give ya.
What injectors... ?