I found out that my alternator is 190 amps, so I'm looking at a 1k-1.2k system now for sure.
Thinking I'm going to try out a pair of NVX subs:
NVX VSW104v3 10"
I'm not sure what kind of amp I want to get. I know you want to match the RMS, and each sub is 500 RMS, but would getting a 1200 watt...