I did that to mine (Talon not Pioneer) and gained 1.4 gallons capacity, from 7.3 to 8.75. There was a downside, after a complete fill I'd get a gas smell in the cab on steep, rocky downhills so I extended my vent from under the hood cowl to as far forward as I could. This raised the highest point of the vent line to just under the hood and vented under my winch. I'll occasionally get a dribble of fuel on the trailer after filling but I'm ok with that and the fuel smell is gone in the cab. Details of that mod are linked in my sig for the curious. NOTE: that 1.4 gallon fuel bubble in the tank is a safety feature designed to keep fuel expansion
inside the tank, not dripping on the trailer. We're adults (mostly), use your head.
I rode with a poo poo 1000 something for two days, he got about 9 mpg and I got 16 ish on the same rides. I love the efficiency of the DCT.