Nice transformation! The BFG's are likely rubbing on the rear felt liner in the wheel well. I had to cut some of the felt away on the trailing edge and it stopped. I've got aftermarket crash bars that allow more room, but they still slightly rub at full steer and flex.
Looks great!
I'm running MR309's with zero offset on 33" BFG KM3 tires. Slight rub at full steer, but it has aftermarket crash bars on it to allow room, but I may still remove them.