Dual 4 ohms or dual 2 ohms?

Ohms http://www.bcae1.com/ohm.htm ,2 or 4 ohms will not make a difference in sound quality. Ohms are used to match the subs to the amp. If you’re going to use the KX1200.1 it will put out 1200 watts at 1 ohm. So you should get the Dual 4 Ohm L7's and wire them in parallel http://www.audiobahninc.com/tech/wiring/parallel_parallel_dual_4.pdf to the amp for a 1 ohm load on the amp.

I am thinking about buying 2 kicker L7 12's to replace my three MTX 8000 series 10's. Do you guys think there will be any noticeable power gain going from a 1.33ohm load to a 1 ohm load? I am using a 1500w kicker certified 1200.1amp which is 1 ohm stable.  

My reason for replacing is that I pound extremely hard and my 8000 series are getting worn out. 

Any other good suggestions for hard pounding 12's to go in a sealed enclosure?

I would suggest you take a look at Eclipse Aluminum's

(I would suggest you take a look at Eclipse Aluminum's)

Thanks BBERMAN1. I will most likely go with the Eclipse aluminum's since you and Forbidden talked me into buying my AWESOME Eclipse CD 8443 Head unit and I LOVE IT!!!! 

Also just bought an Alpine CDA 7995 for my truck and it sounds great with its small amps and sub.  Although not as good as my ECLIPSE