I also bought the F1 from this same site, I got them to price match and free shipping from other site, fairly easy to install and didn't have to modify anything and also very little leakage without drainage installed. I highly recommend it. :smileup:I purchased and installed the Bakflip F1 for mine.
http://bakfliptonneaucover.com/dodge_crew_cab_with_rambox___details_
I love it. Flush when closed, opens all the way when you need the bed. Very little leakage, and I still do not have the drainage system installed (requires the stock liner to be removed or modified). Several long trips with it and never had a issues with wet luggage.
I think I payed 800 for mine and was a breeze to install.