Synthetic Lubricants

Benzmac and others,

I know this is a subject that has been covered before.

I have recently acquired a C-class, 1994 with 58,000 miles. I want to use synthetic lubricants such as engine oil, transmission fluid, and differential grease. Is it too late to start???

I see no perceptible oil leaks but I have heard the reports that synthetics, especially engine oil, will make leaks appear when there weren't any before.

I have never used synthetics before so I have no experience base.

Recommended brands? Most of the major brand names have synthetics now. I know of Mobil-1, Amzoil, Redline, etc?

Experience and opinions are appreciated.