There could be several subwoofer drivers that may work well in this cabinet. The most important T/S parameter to look at is VAS. I would avoid car subwoofers because they are designed to operate in a smaller box than normal subs. Your box is 4+ cubic feet (or about 120-130 liters). So look for a subwoofer that has a VAS larger than 4 cu.ft or 130 liters.
The other part is the port tuning. It's a 4.75" port and not that long. Depending on the subwoofer, it could cause a slight peak just before the frequency response rolls off (probably in the 25-35hz area). It really depends on how the driver rolls off the lower frequencies and how the port comes in to compensate for those rolled-off frequencies. It may be difficult to get something exactly, but you could get a very good performer. Madisound has Morel and Scan-Speak subs that are nice. I wouldn't worry about trying to get the super expensive massive subs, like RE Audio or Stereo Integrity. Those are for the nutsos. JL Audio makes a very nice product, but watch for the VAS being too small.
Take out your current subwoofer and make sure of the exact diameter of the hole. Subwoofer sizes can vary slightly, even though they are marketed at 12".
Madisound has dimension drawing on all drivers. You could also check out Parts Express.