what do you guys think of this that have it in your ext cab f150

 

I have no experience with the Sound Ordnance B-8PT, but if you want something for under the seat I would recommend something like one of these boxes:

http://www.supercrewsound.com/commer...Id=84&catId=56

http://www.supercrewsound.com/commer...Id=12&catId=56

When I had my ext cab I put two JL audio 12's under the back seat and it sounded great. If you are just looking to add a little bass to your truck, then I think the Sound Ordnance B-8PT will do the trick. If its heavy bass your after your gonna need something bigger.