So, I got both cars running right! One of my buddies works at a local shop, and he ended up being my second set of hands to install and adjust the clutch cable in the 93 Legacy. We were just hanging around, and he was asking how the STi was, and I told him the issue I was having. He has a 93 Legacy 2.2T, so he's familiar with our cars, and he was dead set on it being related to the fuel system, or the Cylinder 1 Coil Pack itself.
He recommended the BG 44K fuel system cleaner, so I got it instead of going straight to the $127 coil pack. Put it in my fuel tank, filled up on E85, and drove around. After only burning 1/4 tank, the car feels, runs, and idles SO much better. No hesitation anywhere in the RPM range, no jumpy idles, doesn't die out at stop lights like it was before, nothing! I never really bought into fuel cleaners that you'd find at places like Autozone, O'Reily's, or NAPA. For the $25 the bottle costs, its worth it. 70 miles with no CEL so far!
In other news, I gotta get going on installing the parts I've ordered. We're moving June 1st, and plan to be out of the old house May 30th, and I'll be in San Diego on vacation from May 9th-May 17th. I'm gonna go by Subaru and pick up an oil filter and crush ring for the oil change, as well as get some boxes for moving, and swing by a parts store for a couple of cans of PB Blaster for the suspension parts install.