My 56 Imperial has the oil filter cartridge. I have a question, I had a filter that came with the car it was a paper type cartridge. I did not like it because it did not have the gaskets in the center on both ends. I then ordered one from Andy Bearbaum it too came the same way. I then went to NAPA after looking at the metal cartridge that came out of the car ordered me an exact replacement metal cartridge. I am now going to change my oil again. Should I use the paper cartridge or should I trash it and get me a supply of the metal ones from NAPA to have on hand. On the subject of oil and additives. From reading the Imperial owners club site I understand that a lot of Imperial owners like straight 30 weight for their cars. Also some like STP as the only additive recommended. Years ago I used to get and still have the magazine called Skinned Knuckles. Skinned Knuckles recommended that the only additive to use was Marvel Mystery Oil period. I am going to change from 10-30 to 30 weight and just wanted your thoughts. Anthony Lacaria