Nothing wrong with it, but there is a problem with just putting drivers in boxes at random. The box volume and port dimensions (if any) are critical to getting a particulkar sound out of a subwoofer. Box size determines how controlled the response will be along with where resonances are, and how big those resonances will be. Every woofer will respond differently to differnet size boxes. Also, you have to have some way of crossing the sub over. Cross overs for car subs will likely be very different from home cossovers, since the car acoustics usually have a big boost from 60 - 120 Hz, so a car sub will cross out at 60 Hz, and the main speakers will cross in at 120 Hz, which will sound bad in a home system. But I don't see anything fundamentally wrong with using automotive drivers in home if you know what you are doing.
