Quick update. This might turn out Ok after all.

It broke the bank but I picked up an Ver 7 STi motor (EJ207) from an importer, out of a 2002-2003 JDM STi. Apparently it's handbuilt by Subaru, has a IHI VF30 turbo and comes complete with intercooler, wiring, JDM ECU ect.

We had it towed/delivered it to a private shop today (Jun 30) and if all goes well will be driving it by American Independence day. Woo hoo!

It's a drive by cable motor with AVCS. I will need a wiring harness adapter to get the signals to the AVCS and a protune - Egads! No more COBB maps for me.

As long as I use my USDM ECU then I'll avoid emissions issues, and I'll replace the timing belt now as well.

Wish me luck.