My brother and I installed a double din and amp and a probox 09F35018L-400 in his 2008 F250 today.
For one 8" off of 350w rms.. It kicks ass. honestly I think it sounds better than two $50 tens firing down in a $100 box could.
I know for a fact it sounds better than his neighbors 08 f250 which has a JL 13" in the stealthbox off a 1000w Alpine.
ProBox Custom UTV tops and Vehicle-Specific Subwoofers and Enclosures