Cheap gas will do you no good. 91 rating is there to avoid engine knock.I have recently bought a 1995 s320v. I notice the manual calls for 91 octane fuel, claiming any less will damage the catalitic converter. It is not a major problem as I didn't buy this car to save money. I am curious however if 91 octane is realy necessary.
Why feed her something she dosent want to eat?