I just did this today, so I can clarify a few things.

1) You're going to have about 16-20 oz of coolant gush out when you pull the old coolant temp sensor.

2) When I pulled mine, the o-ring was left in the hole, so I wasn't able to jam the new one in right away. Had to fish out the old o-ring and then the new one went in fine.

3) At first the CTS was hard to find but once you find it, access is pretty easy.