This week on The Best of Car Talk, Yousef's quickie oil change place recommended that he use special high mileage/high price oil in his Saturn. Yousef swears the car is performing better, but his fiancee is convinced that Yousef got suckered. Will Tom and Ray be any more sympathetic, or will they try to sell Yousef the Brooklyn Bridge? Elsewhere, Tim found something resembling mayonnaise on his Fury's dipstick. Should he be worried, or should he just make a tuna salad sandwich with it? Also, Tonia likes her next door neighbor but is less fond of the noxious chemicals he uses on his car; Larry wants to convince his wife it's okay to buy a used car from a rental company but a tale from Ray's past may change his mind; and the great Cathy/Kathy challenge. All this and more this week on The Best of Car Talk.