I went with the T304 SS single system from
www.pmtchips.com on my 05 F250 for around $600 including shipping and love it. I live in the north so I went with the highest quality SS for the least amount of cash I could find. These systems are made by Silverline for PMT so they cost less since you don't know they made it till you get it. You can go to
www.ansaautomotive.com/Silverline and listen to a bunch of different clips on the single and dual system. The duals sound pretty sweet but it all depends on how much you want to spend. Hope this helps