Here is the math:

Crossfire front diameter 18 (457mm) + (225*.40(90mm)) = 547mm outside diameter
Crossfire rear diameter 19 (483mm) + (255*.35(90mm)) = 573 outside diameter

Mercedes front diameter 16" (406mm) + (205*.55(113mm)) = 518mm outside diameter
Mercedes rear diameter 16" (406mm) + (225*.50(113mm)) = 518mm outside diameter

Front diameter with spare on will be 1" shorter than other front wheel and 2" shorter than rear wheel
Rear diameter with spare on will be 2 inch shorter than other rear wheel.
This may cause slippage causing the esp to lock the wheel. You would most likely have to drive with it off until it is replaced.