I don't think modern cars are a direct comparison based their ability to run much leaner than, let's say, a 911 running MFI or carbs. I was always under the understanding that the gasoline collected in the oil would hurt the bearings if left for long periods of time. That's why I change the oil in fall before storing them. Admittedly, I have no evidence to back up my actions, but I've done okay in life following the advice of oldtimers
