I-Dom, you might look into pre-made subwoofers if you're on a budget, intend to complete the install yourself and/or haven't donw much of this type of work. You might also consider a subwoofer wiht a built-in amp. Kenwood, SAS Bazooka and JBL make or have made these.
I have a Fosgate amp that bridges to approx. 140 watts (2 ohm) running into a JL Audio microsub 8.2. This system sounds great and should be reproducable for under $500. The subwoofer contains two 8" drivers in a very compact ported box. There are also versions of this with one and three drivers for less and more money, respectively.
My door speakers (Boston Acoustic RS 5.25" components up front and RS coaxials in the rear - all in stock locations) run off of my fairly high-powered head unit and I'm happy with this. This will not annoy as many neighbors as one or more 12" woofers, but it is very tight and goes pretty damn low while the door-mounted components are amazing compared to the stock setup and are completely hidden.
Cason Grover
E0 SVT
