Cerwin Vega makes good stuff, with that being said what you have there was actually used as a large center channel speaker. There was another speaker that should have gone where that large hole is between the subwoofer drivers. Google searching found very limited documentation on that speaker. Cerwin Vega's website doesn't have the manual listed anymore.
What info I was able to find states that those speakers were rated for 150 watts ... I'm assuming from my knowledge of CV products that it is RMS and not peak. Here's what I'd do if I was you: Use it! it will sound great if it works. Take out the small speaker (tweeter) and plug the tweeter hole and the midrange hole (the other large hole I mentioned earlier). Get a subwoofer plate amplifier and mount it on the back of the box. I would not use the crossover built in to the speaker itself, reviews online said it was not well designed from the factory.
As far as plate amplifiers, I'd get one that puts out 300W RMS and call it a day. Now on that speaker plate for the CV's, it says "8 ohms per subwoofer" assuming they are single voice coil, you can parallel wire those down to a 4 Ohm load. I looked on parts-express.com and the only subwoofer plate amp that is close to the power you want is this one:
https://www.parts-express.com/Bash-500S-500W-Digital-Subwoofer-Amplifier-300-752
The reason I linked that one is because all of the others are on backorder ... If you can find one from a different source that is closer to 300W RMS, that would be ideal. If you dont care about having maximum output from those subs, you could go with the 100W plate amplifier that is in stock. It would give you a solid thump, and save some $$$ but would certainly leave a lot of potential speaker output on the table.