how much power before i have tk upgrade

[Raverthug]

So I'm putting in an alpine double din hu and already have an alpine 4 channel amp to push my Bose deck speakers. I'm debating on going with 2 10/12s or removing my back seat and running 4 10/12s or a combo of 2 10s and 2 12s. Not sure yet. They would be alpine trype Rs pushed by alpine amps. If I go with 4 subs I would use 2 amps or 1 amp on the 2 subs. All sub amps will have a cap. With that said how many watts worth of amps can I run before I have to upgrade the amp and battery or have to add battery's.