Why the hell would you drain the block to change the thermostat? What a waste of time. The sealing ring might cause leaks since it's a crush ring, and it will not reseal right. Keep an eye on that spot. I would replace it when you get a chance.
Also, in the future, use the proper spot for jacking. You can put the jack stands on the frame rail behind the LCAB lollypops.
2007 BMW 328Xi Touring, 6 speed