[Is this audio setup I want to do overkill for my needs?]

You've all ready invested into your electrical, I would definitely stick to the higher power set-up.

I would also suggest checking out the Twisted Sounds 2.8K amplifier. It's basically a 3500w board for $600.

They did a dyno on it, and it scored very well:

http://www.caraudio.com/forums/amplifiers/622796-twisted-sounds-new-amp-2-8kw-dynos-included.html

Here is a good round-up testing of a bunch of different AGM batteries:

http://www.stevemeadedesigns.com/board/topic/189121-my-test-group-31-battery-roundup-round-1/

If you have a batteries plus near you, I'd highly suggest checking them out. They have X2Power batteries, which are re-branded Northstar. If you can't get one of those, then i'd be looking into the XS power batteries next.

Wow that is an impressive amp. I can't believe its only $600, maybe I should reconsider getting that one instead of dropping an extra $200 on an amp that puts out around the same power.

[Is this audio setup I want to do overkill for my needs?]

no one here can tell you what you want to daily.

if you start small and it's not enough, sell the subs and amp and put the money towards the larger setup (larger meaning more powerful). If you go with the larger setup, and it's too much, turn the volume down till it's where you want it.

I use XS with no issues, and i've also used duralast AGM's with no issues. if you get the 3500w amp, then upgrade your front battery to an AGM of whatever brand you choose, and a group 31 size or larger AGM for a secondary to help give you a buffer for voltage.

Thank you, after reading this I have decided I would rather have more power then I need and be able to turn it down rather then not enough and have to buy everything all over again.

[Is this audio setup I want to do overkill for my needs?]

I have been thinking of getting two Sundown D4 X-18s and power them with a Crescendo BC 3500 @ 1ohm.

Right now I already have done the big 3 with 2/0 awg OFC and have a singer alt 270 amps sitting in a box ready to be installed. I have a S800.4 atm powering 2 Crescendo tweeters and 2 Crescendo mids already hooked up but wanted to drop in some subwoofers now.

Should I go with the Sundown Xs and the BC 3500 for daily use? Otherwise I was going to save my money and just get two Sundown SA-18s with a S1500.1 for daily use.

I still am running my stock battery so any suggestions for what type of battery I should get Optima, XS power, Kintek, etc would greatly be appreciated.