It should not have really been called v power as it's not really designed to improve performance or mpg by all accounts but it should have been called "city" diesel because of the cleaner less sooty burn. Also as it's a good engine cleaner and lubrication any improvements I'n both mpg and performance could be more down to a cleaner smoother engine ( factory fresh ) petrol on the other hand has been designed to improve performance but only I'n cars that have an adaptive ecu. The seat range have a stock ecu parameter to run with 95-98 Ron so you would notice a minimal difference.