So many on this forum have asked if there were a lower-temp thermostat available but not so low that it'd cause the ECU to go into "startup" fueling mode. This should do the trick. It's compatible (in fact must be used) with the Mercedes-Benz 1132030275 thermostat housing (that's the OE Crossfire thermostat/housing gents!). The OE thermostat is 188.6F so your car should run about 9 degrees (F) cooler.
https://www.vrpspeed.com/product/mmts-mb55-03l/

 

This may be the same one, a little cheaper.
https://www.mishimoto.com/mercedes-e...2003-2006.html

 

Great catch. As they say, "Twenty bucks is twenty bucks!"

 

I just happened to have an OE Crossfire thermostat in the garage.

It comes already fitted into the aluminum housing. Yo see here the two "wings" on the thermostat which slot into these grooves on the housing. It's a secure pressure-fit between here and the second round stamping on the thermostat which seats into the housing...

...which you see here.

Inside the housing the pintle of the thermostat fits into this nipple-extension. I couldn't photograph at an angle which lets you appreciate the length of these pieces inside the housing.
I'm sure a machine fit the thermostat into the housing but ask yourself, "Is a machine more capable than you are?" :-)