i got the adjustable cable/quadrant from D&D and its great. the quadrant is an aluminum Steeda unit. I do wish i would have gotten a firewall adjuster at the same time. It makes it alot easier to adjust (instead of crawling under the car). So i'd get one if I were you.
About your list of things to do. Mass air conversion is wayyy down the road for you. Speed density will work fine with mods (with proper tuning) and you could run 12's before you should switch over to mass air. I converted mine because i found a meter and computer cheap, so i said what the hell.
I'd go with gears and exhaust first (after a full tune up ofcourse). You'll notice a huge gain over stock with just this. But soon after, you'll want more. you could go with some underdrive pulleys, subframes to stiffen her up a little, 65mm TB, 1.7RR's, with speed density its always nice to have an adjustable fuel pressure regulator for future tuning use. This'll get you started spendin that dough.
good luck