8100lb boat and trailer (max on my 2010 3.55 CC is 8250lbs), 55-65mph, 3.55 gears, 250 mile round trip, 10.5mpg and no problem in the mountains around here. Except for a little butt clenching on a couple off camber turns on steep downhill grades it did fine, but you knew there was a lot of weight back there the whole time. I wont be towing the boat that far often, but it does easily tow my 18' open car trailer with a 3300lb car on it.

My last truck was '07 2500HD duramax and you wouldnt even know that boat was back there, nor the 28' enclosed trailer I used to tow with it. But I can tell you right now there is no way I would even try to tow that enclosed trailer with this 1500 CC for any distance. I towed it without the car once, about 7500lbs or so, and even with a very nice equalizer hitch it was struggling and a white knuckle ride through the mountains, buit was a one way ride to drop it off to the buyer so I did it. 150 miles or so was about 7mpg but that was going into a stiff headwind.

I didn't buy this to tow big, that's what 2500s are for, granted the diesel GMC rode pretty nice but it was no daily driver and once I sold the big trailer I had no use for it and bought this one. I like this truck but its more an SUV with a bed to me.

 

Nope thats why common sense dictates the mere fact that not everyone is gonna experience the same thing, especially when your pulling a building on wheels.