Well seeing as new PS pumps are discontinued and the current reman'd Delcos are probally done by the mass rebuilders than the PS pump is the same IMO. I dont have anything to add on the WP. I've always had spares laying around so it was a no brainer for me. The last time I had to change a WP on a Buick was at least 10 years and maybe 20,000 miles ago. I've never had a problem with them anyway. They seem to be built better than, say the LT1 on my Roadmaster. It eats a pump every year it seems. I'm thinking the POS doesn't like the high silica content in the green anti-freeze. I'm switching over to RMI-25 and H2O when the current one bites the dust. Its probally why I dont have a problem with the Buicks.