I'm buying 2 12" Kicker subs, would a 4- channel 1600W amp be a good choice to power them?

There's no sense in buying a 4channel for 2 subs. Just look for an amp that is 600x1 RMS@2ohms. Also, I would steer clear of power acoustic, jensen, boss, hitron, legacy, lanzar and any other junk brands. Get a reputable brand for good sound quality AND to get an amp that lasts.