I don't know what you mean that the 3.8 is NOT the 311 hp engine.
There is a definite difference if I fill up using 93 octane. When done, my wallet is about $10 thinner. Car drives the same.
I like that it has a lard ass. I think it helps the ride comfort.
I don't even get that in my 3.8 driving it like Morgan Freeman.I run non ethanol in everything I own, I believe my Genny runs better on it. I average 28mpg with 5.0 sometimes it goes up to 34mpg believe it or not! Of course that is no red lights or stop signs. Love my Genny!!