I had routine work done on my '06 X3 this past Friday, oil change, anti freeze etc. I told them I was experiencing lag with acceleration on the highway. Basically it took at least a second for acceleration to kick in when I pushed on the accelerator. Long story short, a diagnostic was done on the computer which reported an error with the transmission. They reprogrammed the computer (took 5 hours) and now I have 0 lag. It's like driving a brand new car.

If anyone experiences lag with their '06 X3, have them check it out.

Did you have to pay five hours labor or do you have a service plan.

Everything was free of charge, I'm still under warranty :)