I picked up my '05 Envoy XL 4WD last May to tow my boat. 173000 on the odometer when I bought it (178k now). I don't have plans for it other than to keep it running as long as possible for towing. Since May, I've drained and refilled pretty much all the fluids (and filters) except brakes and power steering. I've replaced plugs, serpentine belt, thermostat, motor mounts, rear HVAC actuators, washer fluid pumps, and cleaned the throttle body. It runs really well.