The 31"s will fit no problems. There is a tire fitment thread in here somewhere. Pro-active stuff. All fluid changes, using lubricants as directed by the FSM. Such as GL4 for the Manual trans. Mitsubishi or Hyundai Auto trans fluid if an automatic. A complete cooling system flush using Thermocure anddistilled water, emptying out via the blocks water drains. Fit a new OEM radiator cap and thermostat. You really want to be proactive, get the radiator rodded and cleaned. Don't let anyone talk you into a crappy plastic and aluminum radiator. There's a start