I don't know what materials that NHT 1259 uses in its construction, but I do know that it was engineered for home use. With that in mind, a car's environment is pretty harsh. I would consider that factor when choosing a sub. One that I have had experience with and can say whole-heartedly is an excellent automotive sub is the Image Dynamics IDQ. A lot of people on my car audio forum use them. I decided to buy my brother one to see what they sounded like. I got him the 10" and he put it in the recommended 0.65 cubic foot sealed enclosure. With only 150 Watts, this thing sounded beautiful. They play VERY low and don't require a lot of space or power. I would say 200-250W for a 12" would be perfect.

As for amps, there is an amplifier manufacturer that is offering memebers of my board a special discount. The price is so low, they won't let us tell anyone what it is without blowing the deal. Last I heard, the deal was good through 12-25, but I would imagine that if you called them after and asked about it, they would honor it. Go to http://www.arcaudio.com and look up their contact information there. The guy's name you need to talk with is Demetrios. All reports have been extremely favorable with these amps. Very high quality and extremely clean sounding. Some have replaced their PPI Power Class amps with these and have not looked back. Be sure to mention that you are part of the Elite Car Audio group buy if you want to get the price.

For the record, there are a LOT of head units out there that I would buy before AIWA and Kenwood. Look at Alpine and Eclipse. There are some affordable models out there, and you can't beat their quality.