Elvis, I bought 2 pair of (relatively) cheap Alpine Type S speakers from EW to put in my old lady's car, and they sound a lot better than I was expecting. They are 6x9, but I'm pretty sure they make a 5x7 as well. I also have used some of the lower-level (cheaper) JL lines in the past with good results. You might check those out, as well as whatever else EW has to offer. I would definitely amplify your front speakers at least, and probably all 4 since it's a vert, and obviously the sub. Don't waste time trying to run anything off of the head unit power.
Adam, you have a car audio hookup? Know anyone that does good fiberglass work for less than a billion dollars? I need my front door panels glassed to hold my 8" midbass drivers. No need for paint, as I'll be covering them in suede. Depending on how that turns out, and price, I may do a custom center console, too.
Sorry for the thread hijack!