200a will do fine..i have a 200a one cumin..for 2500wrms...so no need to go to 250a and spend more money....if u dont feel comfortable with 200a just throw another batterie in the back and u should be fine.... just remembber wen u get hO alt make sure to upgrade ur batter to a stinger bat or a yellow top in the back and red top as ur starter bat
thats what I have i have a 2500wattrms amp and alpine type X and I had stock alternator and an extra yellowtop just 1 and I was maintaining 14V all the time didnt drop much it was working fine really no need for a bigger alternator