I've had a supercrewsound dual 12" box in my 02 ex-cab for a couple of years now. Haven't had any issues with it, other than the tan wasn't that great of a match with the interior. They'll supposedly build custom boxes if you give them the dimensions, thinking about doing that for my aviator.

 

If you really want your subs, then you WILL be lifting the seat and building your own enclosure. I have two 12" shallow Rockfords (P3S) under my seats in my super crew and I barely got the box to fit totally under the seats without a seat lift, and with all the proper air space. Also, the seats sit totally down like stock. Your only other option is to build an enclosure that incorporates the seats into it to retain stock seat seating.