Looks like a nice car.
There are a number of these cars that develop seemingly intractable stalling and rough running problems around 200K. Head gaskets, AC, and oil leaks are also problems as these cars age. You might want to search on "300E AND stalling" or "300E AND rough idle"
I had a 300E 5-speed for four years and loved the car, but an intermittent stalling problem that no one could diagnose finally caused me to sell it. It is getting hard to find shops to work competently on these cars when they have problems, at least in the DC area and several other places judging from the posts.
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe