I only noticed a very slight valvetrain noise reduction when moving up in viscosity. Other than that, everything is subjective and opinion. I've tried PUP 5W-30 in a noisy Hyundai Lambda II 3.3L engine, and it didn't sound any different than Mobil 1 EP 5W-30, Castrol EDGE 0W-40, or Mobil 1 FS 5W-40 in the same engine. I did notice, however, a slight improvement in fuel economy by going thinner in the same engine. I'm running M1 EP 5W-30 in it again, probably for the long haul.
I care about wear control and engine cleanliness. I honestly don't know how well Pennzoil performs in that regard compared to Mobil 1 and AMSOIL. I want to think that Pennzoil, a rebranded Shell Helix Ultra product performs well. For a small blender, AMSOIL, sure enough, conducts plenty of testing for its lubricants. But I have yet to read from folks who ran this stuff for several hundred thousand miles in the same engine, and it's still running well. I've seen folks running Mobil 1 in the same engine for several years with excellent results. There is a 2014 RAM 1500 on the RamForum with over 300K miles on the clock fed a steady diet of M1 EP 5W-20 with 15K OCIs. I've even seen RedLine 5W-30 run in two HEMIs for over 100K miles. I'd like to see something similar with PUP.
And that's concerning because additives make up a small but significant percentage of the total lubricant.
They probably are, and we could maybe and *only* split hairs under extreme conditions.
Definitively RAM!