I have a trailing arm taken from a 1991 300SE which is my car. The car needed a wheel bearing in that arm and it was cheaper to replace the whole arm than to find someone who would do the wheel bearing. I have that trailing arm for the right rear if you would want to replace the wheel bearing.
I would sell the whole arm for $20 plus shipping. Let me know. In the meantime you can check out the replacement bearing cost. BTW, the car only has 97,000 miles on it.