rear axle ratio change better towing capacity

Thanks for the replies. If we could find a mechanic that would do it for 1000$ I would do it in a blink of an eye but hubby wants to do it himself cause it is very unlikely he says to get it done for 1000$ in Canada. I am just scared about the computer and transmission tuning I have heard about when attempting to change gears. Some even say it has to be factory made and cannot be changed :(