Low budget system, but it sounds pretty damn good. I had everything except the head unit already. I sold a couple things on ebay awhile back and made enough to cover the price of a Pioneer receiver. I put one in my wife's civic and really liked the power, iPod controls, remote, etc...
Before
After
The front speakers are Infinity Reference 5-1/4" components I had in the rear deck of the Civic but never sounded right. I replaced them with some Rockford Fosgate 6x9s and her car bumps now.
Before
After
The tweeters are mounted in the dash and the woofers are in flush-mount MDF rings painted with rattle-can bedliner.
Crossovers are mounted in the dash, the passenger side in the glovebox area and the driver's side against the firewall pad inside the dash speaker hole.
The rear speakers were free and came out of the car I got the dash & center console out of. I just cut out the package tray cover I made and pulled/stapled the fabric under.