I have to agree on the GC and AGX choice. They'll give you what you need at a decent price. A set of full coilovers will cost more than you want to spend and give you barely adequate streetability that will take some getting used to.
I noticed my Helix DNAs mentioned a little earlier. The $1000 price tag is supposed to be an "introductory" price since they're relatively new to the market. I don't know what the actual full price will turn out to be, if it is even really more than that.
At any rate, based on the criteria you listed, I'd skip them. They're not bad - ultimately I prefer them over the stock suspension - but they have a bit of a design flaw that Cory and I learned about the hard way. They are definitely ride-height adjustable, but raising the rear end all the way barely gets you 14" from wheel center to fender lip. That means that your
highest possible ride will actually be the
lowest recommended ride height for a WRX. That certainly won't get you raised for the winter.
When it comes time for me to replace these, I'll probably just go with the GC/AGX combo, myself.