[TahoeM3]

I haven't heard that about the Dinan tune...let us know what they say.

I think your times compare pretty favorably with a stock X5M...keep in mind that the M has a lot of other things besides overall hp and tq that help it go fast. The launch control alone is probably worth a few tenths and mph in a 1/4 mi run. And during a launch control run the shifts are much faster than normal, and faster than those that are set up on the 8-speed with Dinan.

I agree that with the tune the 50i doesn't feel as much faster at higher speeds as it does at lower speeds, but I think that besides the drag/frontal area/weight issue given that this is an SUV, it is related to 3 things:

- One is airflow. Peak torque is low in the power band and then fades, and the hp really flattens at the top of the power band as the engine runs out of air. An intake is supposedly in the works which should help a lot. In the mean time you can try taking out the charcoal filters which will probably net you 10-15 hp up top. But remember this engine wasn't designed to be a high-rpm screamer.

- The second is the transmission ratios, which are probably less aggressive in 3-5th than in the M and not designed to keep the power in the modified power band that Dinan tuning gives.

- And the third is that the off the line performance is so much better than stock due to loss of that laggy feeling/improved throttle response that everything else feels less significant in comparison.

Overall a good step in the right direction...hopefully later tunes will address and improve upon what they have already done.

One last thing...your engine isn't even broken in yet. It will loosen up more as time goes on and will feel faster as it does. I noticed a significant difference from new to the 3000 miles I currently have on it.