What is the most important maintenance for the BMW M1's engine?

I just purchased a used BMW M1 and want to make sure my engine stays in top shape. I've heard conflicting advice on what the most important maintenance is for the engine. Can you give me some insight?

Without a doubt, the most important maintenance for the BMW M1's engine is regular oil changes. This will ensure your engine stays lubricated and running smoothly. Don't skimp on the type of oil, make sure to use high-quality synthetic oil for best results.

Actually, the most important maintenance is regularly cleaning and replacing the air filter. A dirty air filter can hinder performance and even damage the engine. Make sure to check and replace the air filter every 15,000 miles.

For peak performance, it's essential to regularly replace spark plugs and ignition coils. These components can wear out over time and cause issues with starting and running the engine. Check your owner's manual for the recommended replacement schedule.