WARNING! Don't be fooled into thinking all oil filters are the same! They're not! We've been racing Spec Miata for years, and we've ALWAYS used a Genuine OEM Mazda Oil filter because they have a special anti-drainback valve and spring mechanism that will keep the oil system primed and more importantly, it will keep the oil in the upper cylinder head area, specifically the hydraulic lifters. The oil filters you'll find in your local auto parts stores do not have this feature and you'll notice that when you start your car in the morning, you're engine will probably sound like a sewing machine for the first few minutes. This is the hydraulic lifters being void of oil until the oiling system pumps them up. The proper filter will help keep the upper cylinder primed for cold starts.
Mazda OEM Parts and AccessoriesNA Miata Maintenance and Tune Up|NB Miata Maintenance and Tune Up