Stock tire vs. new tire ...What issues if any?

[04xlt]

I have a 2004 XLT 2wd and I am going to change to a much larger tire this week (Nitto TG 325/60/18). I am wondering if there are any other concerns besides the Speedometer that I should worry about. Brakes? Gears? etc...here is what I found with the tire calculator Any input from the experts will be very helpfull. I have 18 Eagle alloys with a 5 inch backspace and BFG rugged trail 275/65/18 on the truck already and a 2.5 front level going on before the tires do Stock Tire - 235/70R17 >new tire - 325/60R18 Section Width: 9.25 in 235 mm Section Width: 12.79 in 325 mm Rim Diameter: 17 in 431.8 mm Rim Diameter: 18 in 457.2 mm Rim Width Range: Unrecognized tire size. Rim Width Range: 8.5 - 10 in Overall Diameter: 29.95 in 760.73 mm Overall Diameter: 33.35 in 847.09 mm Sidewall Height: 6.47 in 164.33 mm Sidewall Height: 7.67 in 194.81 mm Radius: 14.97 in 380.23 mm Radius: 16.67 in 423.41 mm Circumference: 94.09 in 2389.8 mm Circumference: 104.7 in 2659.3 mm Revs per Mile: 694.4 Revs per Mile: 623.6 Actual Speed: 60 mph 100 km/h Speedometer1: 53.8 mph 89.8 km/h Speedometer Difference: 11.35% too slow Diameter Difference: 10.2% Thanks in advance for any input!