I am really glad you posted this. When you run a hot motor, a lot, a big thing you can do is change the oil, a lot. A frequent fluid change goes a long way. When oil gets really hot, it breaks down real fast. When your dipstick puffs like that, change the oil. These older motors go a long way...
My math says that all four tires need to the same. (AWD) If you go to stagger the width between the rear and the front tires, buyer beware. 17" by 9.5" x 4 = Good math.