I want to upgrade my stereo system in the near future but I don't want voltage drops, dimming head lights Etc. I plan on getting this to put in my 2 Door JK (07)
Should I get a second battery for it? Would I have to get a new alternator to support the second battery? Would just a new alternator be fine? Is there anything else I should be considering? (Different box because this probably won't fit?)

 

Stock should be fine with some caps if all else fails. Caps and a 2nd battery.

 

You will need to purchase a "dual charging system" for maintaining two batteries.

 

Would an isolator work? Would you recommend a diode or solenoid (relay) version?

 

Just purchase a system "Off The Shelf".

Search Results - Quadratec

 

I would start with a good deep cycle battery and see how it does before anything else.

 

Like this?

 

I honestly don't know anything about that battery, but that is the right kind. I went with an Optima yellow top and it does great, and costs a lot less than that one.

 

Should I worry about what watt output a battery has? I couldn't find it for the Yellow Top.

 

Yes you need to make sure that the battery matches the recommended CCA ( cold cranking amps ) rating for your Jeep.