[robaustin]

The rubber gasket should be good to reuse, mine was. The 4127 is 0.5mm bigger in diameter than the stock thermostat. I read that the 63.5mm 4127 still fits but is a little more awkward to install so I just took some emery cloth and reduced the diameter down to 63mm so the thing just goes in easily. Changing the thermostat is really easy if you use the "Meister" method of catching the spilled coolant in a plastic bag and just pouring it back into the overflow tank. Don't forget to put the thermostat in with the bleed hole up.