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Old 10-26-2012, 02:48 AM   #11
Registered User
Join Date: May 2010
Location: Seattle, Washington
Posts: 1,450
My Ride: 2011 135i 6MT
Just run a few tanks of each and compare mileage. You won't kill the car, but cost savings will probably be next to 0.
sea6speed is offline   Reply With Quote