Tires do make a difference on a W201 2.3. I bought many tire sets for my car and every time I tried a different kind. The best by far were the Michelin Pilot. Even though the owner's manual says top speed is 197km/h, I had the car buried past the 220km/h mark with one passenger and full tank of gas.

*Edit - Forgot to mention the tires were 205 55 VR15 as opposed to the 185 65 HR15 stock.

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1989 300CE Astralsilber/Schwarz
1992 300CE Schwarz/Schwarz