I went with my Premier DEH-P680MP head unit, a Premier GM-D7400M amplifier, 4 Infinity Reference 5"x7"'s and a pair of Premier TS-SW1001S4 flat subs in a custom made box, non ported. The system sounds simply awesome. It packs way more punch than I expected, and frankly, more than I need. I have the bass turned down substantial amounts, and it's still thumping. I am not one who is trying to impress the people in the car next to me, but rather, am striving for a good quality sound across the spectrum. This setup did it. However, before I turned the bass down, it was an "impress the car next to me" system.

 

Awesome, I think that looks clean and good. I am thinking about doing something similar, but I really like the lows my 15" gets....