I tow a 5X9 trailer with 1-3 bikes on it at times. No problem (even before the mods)
Drops the MPG a bit. Don't even really know the trailer is there.
Oh, and winter mix fuel drops the MPG a bit also.
That and the fact that the engine (12 mile drive to work) does not get to prime temps much.
I can explain it to you, but, I can't understand it for you.