I know it is of the opinion of some people that we drive big trucks with big engines and therefore shouldn't be concerned with fuel economy but I still would like do do as well as possible. I currently have an ARE topper on my 2006 long bed F150 2WD reg cab with the 5.4L. is the fuel savings from reduced drag of an open bed offset by the added weight of the topper? Would I be better off going with a roll up tonneau? Is it all a wash? What do the experts say?