My system is going to be powered by a Rockford Fosgate 250a2 and a 600a4. Do i need a capacitor for this install? If so, what kind? Thanks!

 

Install the system first, then see if you need a cap. Run the system at full blast with the other accessories on and test the charging system with a multimeter. It's an easy thing to add if needed. The Maxima has a fairly strong alternator, so you might not need a cap. I don't use one.

 

I agree with Micah. Try it out first and see what happens. for the most part you should be fine. I recommend upgrading the car's negative battery terminal wire and alternator ground wires to at least 6G but preferrably 4G.

If then you have a power problem where your lights dim then think about the addition of a capacitor.