Dropping new gears in your axle is relatively easy aside from getting the larger pinion nuts free. Setting the gearing up with the right backlash and pattern is rather difficult and not very friendly to error in the long run. A lot of trail only rigs get away with shade tree installs, a daily driver is best left to a profesional with the right tools and know how to set it up right, the first time. Getting an axle regeared can run you anywhere from $400 to $800 at a shop.