Code compliance issue is no longer - gave the compliance officer a call and he was extremely easy to work with. Donor husk is in the garage for the time being, but apparently a car cover will suffice if I need to move it back out into the drive.
That out of the way, we got the first test fitting of the EJ out of the way yesterday. It would appear that with only a slight extension of the mounting slots on the original crossmember, the new engine should drop right into it, but as expected the fit is very, very tight. It could (by my measurements anyway) be done without notching the frame, however that would leave mere millimeters of clearance at the back of the valve covers. It will still be a much tighter fit than its original chassis even with notching, so like past builders I will also be notching the frame. (Noted where I'm notching things out in blue sharpie in the photo.) I should have about a half inch of clearance on either side when that's complete unless I find a way to relocate that forward mounting bolt for the subframe - in which case I can probably get a little more.
I also have 99% of the original wiring harness out of the donor now, and I'm pretty decided on attempting a full retrofit of most of the newer components into the old car, including the HVAC system. By my eye everything *should* fit, but it will be extremely tight.
Since I'm also going as far as installing pretty much everything else of note from the impreza, I'm also considering either adapting the power steering rack to fit the old Brat crossmember, or adapting the Impreza crossmember to fit the Brat, although I suspect the simplest route would be to ditch the power steering in its entirety and just use the original Brat steering gear. My only concern there would be replacement of components on the steering gear down the line - I hate having to track down parts for weeks or months at a time.
These next few days I'll be pulling the old 4 speed from the Brat and starting on the frame notching job. Somewhere in there I'm also going to do a refresh on the EJ while it's accessible. Oil pump, rear main seal, timing kit, that kind of thing, but that will likely be after the new year holiday, especially since I forsee a lot of removal and reinstall of the new engine and transmission while i do the fabrication on the crossmember, firewall, and transmission tunnel to get those to fit where they need to be.
PS - as i build on this I'll be putting the parts and pieces I no longer need up for sale, including the complete but now partially disassembled EA71 engine. Maybe someone with more patience or skill can get that head free and give this thing a new life. Same goes with the transmission and other miscellaneous components as I go.