I think you'll find that with the weight your pulling and the length of your TT (wind drag, forget about the slopped front) that even punching the gas pedal with E85 it's not going to rocket anywhere. Just getting a few more HP/TQ isn't going to drasticaly change your accelleration factor. I went from a 310 hp-360TQ gasser to 350 hp-800tq diesel and yes I have tons more power but it's not like I can all of a sudden light up the tires when doing 55mph with the trailer in tow. I can go faster up hills/ merge into traffic, etc but I still have to be conservitive with my actions. Theres still other cars out there that determine my actions. I garrantee if you have to punch the gas for any reason and have 7000lbs behind you, E85 gas isn't going be the determing factor for your results. If you can save $$$ then go for it.