Does any one know the biggest size sub box that will fit good in
the trunk ? length width height ? and has anybody used or heard what the custom fit ones from Q logic sound like the one they make special fit and color to match your interior with either 2 10's or 12's ?

 

The Q-logic boxes are not worth the money. They flex too much. Check out www.subthump.com As far as the LARGEST box you can fit back there..... depends. Are you willing to remove those two side plastic panels, the spare tire and jack? Are we using wood or is fiberglass doable?

 

Using 3/4" MDF, I've got a 3.95 cubic foot enclosure in mine. I can even expand it a tad here and there and get a little more space. I think I can get 4 cubic feet out of the full well using MDF.

 

I have a deep well Ttop box FS that has a lil more than 1.5 cubic feet per 12 inch sub (2 12's, specifically brahmas). You can still use the ttops piggybacked, and can be seen on subthumps site. Its an awesome box and the brahmas absolutely pounded in it. I'm sure if you wanted to go with one sub or share the airspace with several subs you could squeeze out more, like lwillman did.
Brian

 

Thanks for the info.