I have a 1991 Mercedes 300E that has handling issues. The flex plate and bushings were replaced about 1 mo. Ago due to a vandalism incident but even before then I noticed that when I accelerated to any speed above 45mph or so the front end feels very loose and like it is drifting. The best way I can describe it is that it feels like driving on marbles. Thought it was the tires so I just had the front tires replaced and balanced. If anything, it is worse than it was before. I can only drive 30 mph before you can feel a very noticeable drifting and then feels wobbly trying to gain control and drive straight in my lane. There is also a squeaking noise in the front end whenever I am going slow and the pavement level changes or I turn the wheels. What can be causing all this and how can I fix it?