37x12.5x17 help with decission

[MarineHawk]

I put about 50K mi on my Cooper 37" STT tires on my 06 H2. i replaced them a couple of months ago. I loved the STTs, and wanted to buy another pair. I honestly think they have the best traction across the spectrum of any offroad tire I have ever owned. But I was having just enough rubbing at full turn to make me want to solve that problem.
The 37" Coopers are 13.1" wide (according to specs--though enumerated as 12.5-inch). The 37" BFG KM2s are supposedly a true 12.5" wide. So, I went with the KM2s. I also put on some Moto-Metal wheels with in inch less backspacing--4.5"; the stock ones have 5.5".

I now have no rubbing at all ever. Also, and I cannot explain this at all: I constantly monitor my mpgs every day (just bored, I suppose). I had a local shop install the tires and wheels. I also had a new allignment and Royal Purple (had been using Mobile 1). I don't know which among those factors have strangely caused this, but I am getting somewhere between 0.5 and 0.7 better mpgs--consistently with the exact same driving patters. It makes no sense to me, but it's definitely gone up.