When you drop the subframe, but a jack under the diff, it's pretty well balanced around it, although the front is a little heavier, but it's really no big deal. It's much more of a pain to get it back in.
You should check out the Megan Racing roll center adjuster ball joints. I don't normally recommend Megan Racing anything to anyone, but they're really the only ones that make them right now. They're $168 for a pair, which is cheaper than complete arms.
Megan Racing
Megan Racing
You'd probably want to do all four, but they're due for replacement in any S13 anway, so why not? It can only help.
I'm not that far away from you, and I'm always down for wrenching on a buddies car, I just need to get my car fixed first, but if you ever want some help...