The 2.4 owners say the same thing when they install the hot air intake also.

Numbers wise, the 2.2 standard and the 2.4 auto run neck in neck 0-60 & 1/4 times. That just shows you how good that auto is.

 

I bought my 2.4 1lt last april and have put approx 60000k on it since. For the first while I was using regular gas as I am on a company gas card and wanted to save cash. The engine was less responsive, noisier and a bit thrashy. (I am a bit more sensitive than some as I spend 80% of my waking hours in the car) After using premium a couple of times and noticing how much more refined the car feels I renegotiated my work contract to allow me use of high octane at all times. I feel a difference for sure. Especially when merging on the highway. There is no lag between the pedal being depressed and the car moving. Also much less pinging in the engine when cold.