TFucili, IMHO I would think that a combination of a bubble front and "Air Tabs" on the rear would have a positive effect on fuel mileage. Having said that you may wish to do a cost/benefit analysis to determine if this is the correct course of action for your situation, ie how much towing do you do? Good luck with your efforts!
TDR member, gathomas
I tow 33' 5er with 97 Ram CTD 3500