When my S320L was just 1 year old, it used to run at around 80 c.(75 in highway & 85 at go-and -stop traffic). However, it may not be good for the engine to run at that low temperature as the engine components are not working at their optimal temp. that may increase the wear of them. As a result, I got the 72c thermostat replaced by a 87c one to make sure my engine is running happily.
Just my opinion...