Baja 1000,here I come!.
First,consider the dimensions of the wheelwell,plus the 'offset' and diameter of the rims which are to be installed. This determines which size tires are feasible to mount to...
It will do 65 on a flat road pretty easily. I have had mine up to 70 on a downhill flat asphalt road. It is not the fastest ute out there but it will hold its own and provide the most comfortable...