Id also reccomend this passive EQ with built in crossover:
http://www.amazon.com/dp/B00079RNOA?...0&linkCode=asn
Ive used it in several vehicle systems in the past and for the $ is a great component!

 

Sorry to inform you of this Semigod, but it's a piece of junk, not specifically the one you have the link to but any and all dash mounted EQ's should be tossed in the garbage. They create more problems than do good. The noise floor goes through the roof with those things and they tend to have lots of backround noises like hums/engine whine and speaker pop. However, it will make your speakers sound better than without, but you will be bringing on a lot of issue's. I have had the dash mount before and only bought it for the price not quality. I have gone to trunk mount eq's and trust me when I say I will NEVER go back!!!
For non electrical savvy guys I would reccomend the JL cleansweep or the Rockford 3sixty.2 Little pricey, but it's a plug'n play, no power needed for the rockford and no adjusting anything. Plug in and turn on the radio.

 

dirtydog, ive used that specific piece on more than 1 car and NEVER had any issues with it.