Why though? You're got simliar tyres on a similiar vehicle in your garage already, so why bother putting mud tyres on both? Personally speaking I find mud tyres are pretty shit for highway driving so; unless you drive 100% on unpaved roads am not sure why you would want to replace perfectly viable highway tires with mud tyres when you already have them installed on the other SUV? Since you live in the same household, I'm assuming you get to drive both vehicles? So why not have road tyres / highway tyres on one and mud tyres on the other? That way you have the best of both worlds?