2 10" MB Quarts, sealed box, and ran off a RF 600 watt amp.... In my 5.0, sounded great but didn't get loud by any means.
First "loud" system i had was... 15" RF Power hx2.. 4.5ft3@30hz w/ a ton of port area.. Kicker kx1200.1. Was in my Jeep grand cherokee, was so nasty on low notes.