Guidance needed: 2 lvl 4's with XL uprgrades

[TNichy]

I'm running 2 lvl 4 12's with the Xl upgrades, as stated. I'm looking for some thoughts about the box I've built for them. The boxes exterior dimensions are 26 wide 18 deep and 18 tall. Torres calculated the interior air space to be approx. 3.86ft3 with approx. 12.79in2 of of port per ft3. The port is 5.5in2 by about 26 inches long. The concern I'm having is that (by my very untrained eye) I'm getting more excursion out of one sub than the other. These are being pushed by a DC Audio 3.5k with stock alt. I wasn't able to check voltage at amp while pushing on it, but with Jeep idling it was metered at 13.7 volts.

Obviously the box wasn't finished when pics were taken, but I wanted to make sure I give an idea of what I was dealing with.

Thank you in advance for any and all help, and suggestions and criticisms are acceptable, but please take it kinda easy on me.

Edited May 17, 2013 by TNichy

[CJ18]

Check and make sure you are wired correctly. Port seems to be centered so that shouldn't be causing the issue.

[TNichy]

I'll check that out. Thanks