There are a few tricks to driving the 4.0 and making it go. Don't pedal to the metal. This makes for late shifts. If you shift on your own, get it into second quick (back off the pedal a little), and shift at around 3500 RPM into third.
Learning how to drive it, makes it much more enjoyable, I can get a 3 series BMW most every time 0-60.
Use your torque and stay out of the high RPM band. Just because the motor is making noise in the higher RPM bands, doesn't necessarily mean it's accelerating at maximum.