I bought my '06 MCS and thought the same thing about the throttle response. It was awful compared to the cable linked throttles I'd been used to.
I brought it home and read up on it some and decided to reset the ECU and go drive it like I wanted, rather than how the dealership/previous owner had driven it. This made a noticeable difference in how it felt. I'm not as experienced as most of the posters on this forum, but I know what I felt prior to and after resetting the ECU. It still has throttle lag, but it was pronounced and almost dangerous prior.
I used the method from the inside of the car, using the on board computer. Lemme see if I can find the steps again.
The throttle was markedly more responsive after resetting it and driving it in a spirited manner for a few miles. I'm not going to say that it 100% removed throttle lag, but it made it not so much an issue that I don't mind it anymore.
I know the real way to do it would be to have a tuner flash the ECU or to have BMW service remove the adaptations. All I know is that before I did this, the lag was so pronounced that it was dangerous if I was trying to shoot a gap pulling out in traffic or especially when turning left in front of on coming traffic. After doing this procedure, I don't have to worry about it at all. When I first test drove the car the throttle lag was really hard to get used to and I almost stalled it twice in the parking lot trying to feel for mesh point with proper rpms.
There is an assumption that the concern is tune?ECU related? The first measure is to determine the engine and running gears condition. While it may not be apparent in the daily driving but you may have a mechanical to toss into the equation of your concern? Do a simple compression check of the engine. Also carefully look at all the other power producing components. i.e. air filter, *spark plugs, *wires, intake boots, vacuum/air lines...etc. If after all these have been effectively ruled out than continue with the "GREAT" suggestions here on this thread. To augment adding a product or procedure increasing an engine output also increases an existing questionable power train condition as well.
Minidave Another good point to think about is how one is comparing the throttle lag or lack/loss of familiar throttle response. Most of us without a frame of reference comparing another MINIs performance really do not know what we are missing or not? Also a review of all the dyno graphs can show why throttle response at low rpw is apparent. Not much torque or HP to move a 2500lb+ object? Now place into the equation components of engine parasitic drag such as AC compressors or Alternators running high output and you have a partial answer to the question of throttle response?
