Would this amp push my 2 13.5" w6v2 subs?

For starters subs are wired in different configurations to produce a different resistance at the amplifier, so your subs are not exactly stable at 1.5 or 3 ohms, they can just be wired to a 1.5 or 3ohm load. However I think that your subwoofers have dual 4 ohm voicecoils which means that they can only wire the woofers to a 1 ohm or 4 ohm load. And the alpine amp you posted is not stable at 1 ohm, so you would have to wire the subs to a 4 ohm load and would only get 600 watts out of the amp. You may want to look at a 1 ohm stable mono amp that produces about 1000 watts or a little more at 1 ohm. As for the battery/alternator situation, I don't know the ampere rating of your stock alternator but generally speaking a stock alternator can handle up to about a 1000 watt system but that is on the high end and will probably stress the system. To be safe you can upgrade to a high output alternator and that should take care of any issues. Do not get a second battery without upgrading the alternator however, the added strain of having to charge two batteries will only hurt the stock electrical system.