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			The Porsche 930 M/C is a 23mm diameter (both pistons) model.  The beetle standard one is 19mm diameter (both pistons) so it should be more 'powerful'.  However, M/C piston size selection is very often down to the preference of the individual driver - power verses length of stroke. 
 
Clive
		 
		
		
		
		
		
		
		
		
	
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