2000 nissan maxima woofer

If you're just looking to put something in as a replacement and use the factory amp, here's a couple things to consider.  You need to make sure your factory amp will handle the impedence load from the new woofer (how many ohms is it compared to the old one- higher is okay, less is not).  Also, if your woofer is designed to run as the factory one did (in the same size enclosure as the factory woofer, or free-air if it's mounted to the rear deck). 

Personally, I'd consider an aftermarket amp/box as well.