good sub setup?

hello all i want to finally upgrade my stock sound system and i'm looking to add a 12" Kicker CVX (don't know if i should do 2 or 4 ohm) and run it with an alpine PDX 1.600 amp. i have no idea what deck im getting but it will be something....obviously.........will this setup suffice my bass craving? and if i don't upgrade my 4 6x9's will i still be able to hear the high's and mid range or would i need to upgrade all the speakers


THANKS