Tires can have that effect also. What tires are on the car? How many miles are on them? Are they the stock size? What are the air pressures?

You may want to switch them side to side, and back to front, and see if this has an effect. Tires are the cause of many weird handling problems. Are you using the stock MB wheels? If not, are the off-sets in spec?

Hope you find the culprit(s).

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Calogero, from the movie, "A BRONX TALE."