you should be fine. a 2000W amp should only draw like 100 amps. my 2 1000W DHD amps draw 60 amps a piece and they are 4 channel each. my alternater will keep up with them, though my lights will dim when i got er boomin. i think a stock alternater puts out like 180amp anyways so you should be fine. you will have to buy an alternater pretty quick if you dont have a capaciter on your amp because of the constant loading and unloading the amp will put on the alternater. i had to do it and i got the lifetime warrenty on it to so when it goes i just take the 3 bolts off unplug it and take er back in the store just raisin hell about how junky there parts are.
they are happy to give me a brand spankin new one to to get me outa the store.