My stealer only charged me $8 for a Purlux in an AC 2244G box. I can pick up Purolator L 15436's for $3-4. Pep Boys has a good sale this week on them. I think the ST 9018 is less than $6, likely identical to the STP. The Fram CH 9018 looks just as good, but Wally's wants $12 for them.
This is the firs report I have ever seen here of problems with a cartridge filter. You pull the naked cartridge out, and you should spot any problems. Somebody been running 20W-50?
I am still waiting for a good answer on why you pay an arm and a leg for a filter with plastic end caps and no metal housing, no ADBV, no bypass. I say, rip off.