I haven't tried a lot of different oils, but have used Quaker State Horsepower, Rotella T6, and lots of PP and Ultra (haven't tried the new formulas). Using Mobil 1 now in our SUV, brother's Honda Civic, and Dad's Tundra. All the vehicles are running better, smoother and quieter. It's more noticeable now, with the Artic blast we are having. I started our Dad's truck yesterday morning and the thermometer said 10 degress. So, yes, it was cold, but it fired right up and didn't take long to quiet down and run smoothly. The same thing with my brother's Civic. He talked about taking our Mom shopping yesterday, and I was surprised because he usually doesn't like driving his car in the really cold weather, and when I asked him why, he said the cold doesn't really seem to be affecting the engine that much for some reason, and he wasn't sure why. I reminded him we switched to Mobil 1 this fall, the last few winters have been Pennzoil Ultra. With the Ultra, the engine had a whine to it after starting in the really cold weather, almost like a power steering kind of whine, but it was coming from the engine. He would let it run for a few minutes, and the noise gradually went away as the engine warmed up.
With the Mobil 1, even with the weather being this cold, the engine is quieter on start up, and it doesn't take long for the engine to smooth out and quiet down as it is running.
I really didn't think there could be that much of a difference between the two oils, but there is. We have not done any tune ups to the vehicles recently, no spark plug changes, just changed the oil.
I know it was a long story, but my point is that since you are already using a really good oil (feel free to try a different oil, that's part of the fun) the difference may not be that noticeable.