I've heard with the soloX, the amount of power depends on the application. It is a competition only subwoofer. If you're using it for competition, I've heard of 10,000watts going to the soloX 18 for short burps. That requires too much power to sustain off of any reasonably priced alternator. You would likely need multiple H.O. alternators to keep up with electrical demands. The sub with that much power should be run off a fully charged battery bank.
Sub = 2k
Amps = >2k
Alternators = >1k
Batteries = >1k
Wiring = 500
Installation = ??
I consider this an expert only sub to use for its intended purpose. You need to be ready to invest a large amount of time and money into this subwoofer, or be ready to shell out to a premier installer.
_________________________
just something else i'll accomplish...
| 
