Least efficient mod: Taking my truck on road trips instead of the GF's Cruze...
Personally, I'm fine either way. But she says my truck is more comfortable, has better leg room, and she can bring her many "necessary" bags... If we took the Cruze she'd have to pack sensibly... and we just can't have that now
I buy the gas, she pays for the hotel, food and she carries her many bags herself!
As for the truck itself, I'd say the studded winter tires suck a good 1.5-2 mpg... stupid cold for 5 months of the year doesn't help either...