Bear in mind that when you graduate for a torque arm, you'll need far stiffer rear springs than what you buy for a 4-link, so the rears won't be the last ones you buy for now. And IMHO they're less critical than shocks as long as you get the rate close.
As for the adjustable LCA's, I've never "sprung" for them but they probably are handy for ride-height tuning (easier and better than trimming the springs), and if you ever get involved in corner-weighting, that's where they'll shine.
As for shocks, IMHO the Koni is on the harsh side, but adjustable. Probably better suited once you go torque arm. Bilstein will tend to be mellower but no less capable, but not adjustable, which isn't that big a deal if you follow the correct advice about pairing them with the right spring rate for the application. The only KYB's I'll let near my car anymore are the adjustable AGX and frankly, they'd have to be sharply discounted or free because I don't trust KYB to begin with.