More steps forward today!
I took the leap and pulled the front knuckles & lower control arms from the impreza. No going back now! One of my buddies gave me the great suggestion of putting the car on a pair of small Harbor Freight moving dollies, so $20 and a scrap 4x6 later and I'm still able to push the husk in and out of the shop after all of today's work - which is both great and not so great. Great in that I can keep my neighbors happy for a time longer - not so great in that it's still in my workspace every morning until I push it out of the way 😅.
Enough about my neighbors though - onto the nuts and bolts of the matter!
Jacked up the Impreza and got to disassembly. Not too hard, just took some time to keep nuts and bolts together with their constituent parts and assemblies as I removed things, moving one side of the car at a time. Starting on the drivers side I pulled the CV, knuckle/hub assembly, and lower control arm. The knuckles bolted right onto the new coilovers, however the stock cam bolts at the top from the Impreza don't fit the new coilovers - the holes are too small. Going to have to do a little figuring there but for now they're good enough to hold everything roughly in place. I'm going to have to go digging to see if they come with bolts when new or not. Minor problem.
The lower control arms almost fit perfectly into the mounts on the original subframe. The distances are exactly the same and accomodate the width of the bushing like it was supposed to go in from the factory - only modification required here was opening up the holes a little bit. There's probably a metric equivalent but i took a pair of calipers to the bushing bolts and found that boring out the mount first to 15/32" and then only the front flange to 31/64" with a hand drill will accommodate the bolt with no play. Based on another build I've seen I will need to reinforce the front flange by welding in a thick washer later - suspension action has the potential to make this hole oblong over time. After that, just had to hook up the control arm and knuckle to get an idea of what this will look like.
I loosely reattached the brake caliper bracketry, rotor, and a wheel to get an idea of how this'll sit and I'm pretty tickled with where it's at. I'm going to want to adjust the coilovers longer, these 15" wheels take up a lot of space in the wheel well in comparison to the old 13's.
Now that that's done I'm going to have to mock up a template for the other mount on the control arm - likely will get something cut and bent like the transmission mount so I can just bolt it up and zap it in. I'll have a little peek around under the car tomorrow or early this week - maybe I'll get lucky with another choice bolt hole somewhere.