What has happened to the 2500 rpm growl my 2.5 Subaru engine used to have in my 9-2x Saab? It quieted down when I put SF's MTL-R in the transmission, which was a big surprise. It quieted more when I put GC in the crankcase, and now, it's even quieter with PP in the crankcase. It's NOT Honda/Toyota/Mazda/sewing-machine smooth, but, I enjoyed the growl it used to have. Surely Lube Control couldn't affect noise levels that much (only 4 ounces), LC is new additive used for the first time with the PP. Same with Fuel Power...new additive used for the first time with this PP change. Idle is smoother (intermittant stutter/miss at idle is gone), and lower, but, that shouldn't change the way it sounds at 2500 rpm. I think I better go get my hearing checked.