Having driven 4.0 5 speed at dealer lot, and having rented 3.0 and 4.0 automatics at various times, I would recommend the 4.0 5 speed. I don't know if the 3.0 comes with a 5 speed, but the auto version is way too wimpy and you have to really stomp on the pedal to get it to downshift. It does get slightly better mileage than the 4.0 auto, but I don't believe it gets better than the 4.0 5 speed. The 4.0 auto has a lot more guts than the 3.0 auto, but again, not as much as the 5 speed. For sheer fun and lots more available power, the 4.0 5 speed wins hands down. Automatics should be illegal anyway. Think how many people that would take off the road and leave to those that can drive.