I had the same problem, or issue, with my 2001 3.0 and I did the throttle adaptation reset myself and it significantly increased throttle response; if I press hard on the accelerator from a stop, it just smoothly rockets off without the pause and jerk that it did before the reset. It's been a while so I can't exactly recall the process, but I think I turned the ignition on, but not cranked, and waited 10 seconds and then turned it completely off, then cranked it. This really helped me, but with your X5 being a 2004, you may need the transmission reset after all, but you may want to try the throttle reset first, just to see if it helps.