Hi all. I hope this information can help some people out. I removed the front seat today and did not find any black box modules...only carpet and foam. The foam piece, while not square, had these approximate dimensions. 16.5" W x 10 3/8 D. The height is a little more difficult to share as there is quite a bit of tapering. The largest height dimension is 2.5", the smallest is 1.25".
Although i didnt investigate more than just a quick glance, i do think the wiring harness for the HK amp i still running along the drivers side. I hope so, because i plan on splicing my amp in at that location.

 

I'm confused your title says 2011 and you text says 2007 so which car are you talking about.

And BTW there are different modules in different places depending on year and options. so other people may have modules under the seat.