car: '89 240 wagon, about 233,000 miles question: I change the oil and filter about every 4000 miles, give or take a little. This morning, I stopped at Autozone and picked up a filter for my next change. Their book said the STP filter was S-7328 for .19, and the Fram had essentially the same number. Seemed a little more expensive than the last time, so when I got home, I checked and have been using the STP S-16 filter, which is about a dollar less, but the same general size and shape. Just curious if anyone knows what the difference is between the S-7328 and S-16 (other than the price!)??? Either is cheap enough that I don't really care, just want to use whichever is appropriate....