1. Try putting it in 1st gear, or reverse.

2. For the gearbox, it sounds like your shift linkage is a bit worn out and loose.

3. I'm not very familar with the climate control system on the w201 (190 series ) but it sounds like you could have it stuck on the high fan speed, rather than low or auto. Typically you have an auto setting with a manual low and high override for extreme cases, like a hot summer day.

4. Not too sure about the tires and wheels, but I would reccommend tires and wheels that are close to what was used from the factory. They spend alot of time designing the suspension, which includes the tires, and its all part of a complex system where changing one part will have an affect on the others.
By the way, enjoy the supportive and durable Mercedes seats, and the effecient and seamless Mercedes climate control system. They cater well to the passengers. Much more so than BMW.

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1976 BMW 2002- 100k
1995 BMW 325i 175k
1984 Mercedes Benz 300D Turbo Diesel- 270,000 mi

1981 Mercedes Benz 240D- Estimated 300,000+ mi Returned to the earth