Im trading my 4Runner in and Im getting beat-up on the price. So I want to keep my General Grabber AT2s that are less then a year old. I found a set of used BFG mud terrains for cheap money. But they are pretty beat. The problem is I am driving 5 hours away to pick up a 2010 tacoma and I dont want to mess up the drivetrain. I have a V8 and I know the tires have to VERY close in diameter because of the 4WD system. What is a acceptable variation in size ?