I did a tune-up when I bought the car a few weeks ago with a new fuel filter, new plugs, new plug wires, new PCV, and a new air filter. It is still painfully slow. It a 1997 model years, not sure if that makes it phase 2 or not. I'm running 8-10 psi on my ZX2 with 9.6:1 compression without detonation but I'm only running a max of 16* of timing advance. I'll hook my scanner up to see what advance the Subaru is running, probably more than 16*.
I wouldn't feel comfortable not using an intercooler, even at 6 psi. At 8-10 psi (depends on what mood my wastegate is in) I can tell a difference in charge temperature by just touching the inlet and outlet pipe at the intercooler. I may just get a side mount from a DSM and run that in the fender well.
A VJ11 would be perfect for this project but I think the TE04 (I think that is what came on the GST) would work great as well.
I'll take a look at those threads on NASIOC.
Thank you for the reply.