Ok, i have a 2006 f350 cc drw diesel, FTX off road package (whatever the hell that is...) 54k miles. Stock tires are 245/75/17 bfgs. Im looking at going bigger without a lift, either 285/75/17 toyo mt s or nitto trail grappler, im guessing i need to go with spacers on the rears, i do tow 10k lbs on a regular basis. Thoughts? Opinions? I know the trail grapplers are pretty new but they seem to be getting awesome reviews... thanks, Mike.