You may get some help for both locations from these links:

http://www.benzworld.org/forums/recommended-repair-shops/

Canada - Page 2 - Mercedes-Benz Forum

In Toronto, some years back I dealt with Arthur at Eurocars , 45 Algie Ave in Etobicoke. He replaced engine on my 300D and replaced cracked manifold on my 350SL. In above link McNally in North York seems to be highly thought of.

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5