I just replaced the thermostat on my newly acquired 2009 E320 Bluetech. Car would not get up to 87c unless it was idling. Mostly ran way colder than that. Rarely showed more that 2 bars on the gauge.
First thing is I found I that when I put it on jack stands with the front raised up I could pull the radiator hoses with only a few drops of coolant lost. I just stuck a small pan under the hoses to catch that and cleaned up the rest with a few paper towels. No need to drain the radiator at all.
Easy job although the thermostat comes as an assembly and is expensive, about $170.
Second thing I found was a nice improvement in fuel economy. I bought the car from a dealer and immediately it started showing codes. Dealer checked it and replaced the temp sensor. I took it back in twice about the low temps and they said unless it codes they won't help. Great MB service. By that time I had checked the fuel economy and it was disappointing. Came in under 30 mpg. Last tank went to 27.5. I commute 121 miles daily and I watch the mpg. Last car I had was a 2008 E320 Bluetech and I always found the mpg to come in at 32 to 33.
After repairs the temp gauge showed 87c and first tank was 33 mpg, Over the next few tanks I say that improve. So long as I use the cruise control and don't get crazy I can get into the 35 mpg range. Nice.

 

I'm curious where exactly you placed the jack stands. I've always feared I could damage the underside. A pic would be helpful. Great work!