RepairPal Certified shops can diagnose and repair your 1997 Mercedes-Benz E420. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Unfortunately there is absolutely no way for any shop to answer this question without laying hands on your vehicle. Who diagnosed the specific problem? What was their estimate to repair. How did they come to the diagnosis?
Suggest you take your car to a qualified facility for a diagnosis and estimate.