No I wouldn't think you would. You MIGHT... but I wouldn't think so. I have a stock 70a alt, and my oem battery, with only a big 3 upgrade done for electrical. I've got an eD 9.1 and 9.4 running for a combined 1500w @ 12v. These are also pretty inefficient amps, and I have no voltage problems or dimming problems.
The Sundown amps are known for their efficiency, and you're running a bit more power than me, with a better battery and over twice as strong of an alternator.
Everybody's car is different, so you can never know until you try it, but I think you'll be ok with a big 3. I've heard the yellow-tops aren't really ideal for car audio, so maybe just put the Kinetic under the hood? Either way, I wouldn't really be concerned with running an extra battery in the back. Maybe at the most a little HC600 or something in the back. That's just my input though, maybe someone else will know more about how your car does with bigger systems and what not.