Sounds like we all have noticed the same things.
My journeys did feel more straight line stable on the highway and I had put the 18" sport wheels on both cars. Must be the suspension.
It's also weird how car to car the performance seems to change noticeably. My buddies stock 09 g37s pulls much harder in the upper rev range. It snaps your head back whereas mine doesn't. I told him my tech package must weigh 500 pounds. (Haha)
The fastest of my 3 was my 07 journey with the magnaflow x-pipe as only mod. It beat my friends g37s at the 1/8th mile track repeatedly.