Originally Posted By: sayjac
^^^^I wouldn't be too concerned with the difference in efficiency between the two as much as how long you intend to run the filter, ie., fci. If you plan on running the filter 10+k miles then the PSL would make better sense because of it's greater holding capacity. ~7.5k mi. fci then the P1 would make more sense. That is of course if ROI means anything to you. And, ~13 grams is still a lot of junk for a well maintained engine.
Fwiw, I've seen the PSL listed at Advance Auto for $10.50. Buy in quantity, use an AAP code, and the price is down significantly. But, if the PSL is $25 north of the border then that makes the P1 considerably more cost effective. And afaik in Canada the Bosch Premium is now sold at Walmart and it is a P1 clone.
At the absolute most my OCI would be about 6K miles (9,600 km's) and even that's a bit of a stretch. The $25.00 pricing I found on the PSL was at Amazon.com. If it's that much there I'm afraid to find out what it costs up here. I also checked Advance's website and it sells there for about $20.00.
All that being said, I think sticking with the P1 would be the best for my application because as you mentioned it should be fine in a well maintained engine, which mine is.