replacement drivers

The eminence drivers are a good bet - just bear in mind that each line is good for different things, and how much power output you want.
Personally I'd go for the Legend series as they're (well some of them are) specifically designed for bass guitar.

 

The cabinet and drivers must be precisely matched or they won't work properly. There is software available that makes this an easy task (WinISD at linearteam.org is one source) but without knowing how to use it you're still going to be in ther dark. You should read a book on loudspeaker design to understand what it is you're trying to do before you do it. Check the books available at www.audioxpress.com.

 

There are at least half a dozen common parameters besides impedance (ohms) and wattage (where they catch fire). Use the SEARCH feature and save yourself a lot of money.

www.partsexpress.com

 

Exactly. At the very least you must also consider Qts, Vas, and Le to get an acceptable result. The only thing watts and ohms tell you definitively is at what point you destroy either the driver or the amp, respectively.