my subaru is using 95 octane lead free petrol. this is how i bought it about 3 months ago. i was told they should be using the leaded petrol. it is driving fairly smooth (also regarding it's age..) and only rings a bit going up hill and it is terribly weak doing so..
could i just go back to leaded ?
also, would like to change the spark plugs. would the NGK-R BKR6E that are installed do ?