Second battery for MB B52v3?

I have an '04 B52v3 Team Edition which comes with only one battery. I'd like to get a second battery installed on-switch. Few questions:

1. Is there a specific 'wiring kit' that you can purchase to add a second battery 'in-line/shared' with the first? Or is it better to have the second battery run the stereo, etc separate?

2. How difficult is this to 'to-it-yourself'?

3. Estimated cost of the project?

Thanks in advance!

I was going to do that but did one hc 2000. I run huge system over 4000 watts on one battery. This battery is like 4 batterys in one.http://www.kinetikpower.com/powercells.asp

I found a kit and did it myself, not hard, as long as you take your time. I got what I needed from this place:
http://www.ase-supply.com/Sure_Power_Isolators_kits_s/20.htm

Chris the guy that helped me, explain some stuff was very helpful about what’s involved.

I'll take a look at the ase-supply site. Thanks a ton guys!