I would really see regearing as a waste of money unless you get a good deal on a matching front and rear elocked diff from a 4Runner (typically 4.30 ratio) or get an elocked rear from a tacoma (typically 4.10 which is probably your current gear ratio) and modify to fit in your housing. You are only increasing the tire size by 1 inch. Here's a calculator to compare different gear ratio's and/or tire sizes:
Gear Ratio Calculator select tacoma/fj transfer case to get the proper gear reduction ratio.
Summary:
70 mph 265/70R16 4.10 gearing = 2237 rpm
70 mph 265/75R16 4.10 gearing = 2163 rpm
70 mph 265/75R16 4.30 gearing = 2269 rpm
70 mph 265/75R16 4.56 gearing = 2406 rpm
70 mph 265/75R16 4.88 gearing = 2575 rpm
70 mph 265/75R16 5.29 gearing = 2791 rpm