The 3.73 vs 3.91 Dilemma

Dude the difference is like 100 rpm and you're still only at 2,500 at 75. You won't even notice the difference between the 3.73's and the 3.91's on the freeway.

I mean seriously, go for a drive, see if there's a significant difference in engine sound between 2,400 and 2,500 rpm. Kinda doubt it. But ultimately you have to decide if you can live with it.

My 340 with 26" tires and 3.55's turns just over 3,400 rpm at 75mph and it can do that all day long. I don't know that I'd want to listen to it on a 6 hour drive, but the 30 minutes I commute on the freeway is fine. What's comfortable for you and what's comfortable for the engine are different things.