what you are feeling from the older engine is better throttle response than the newer engine. It makes it feel faster when it gives you that immediate power but as soon as it gets going the new engine will blow it away. The valvetronic slowed the throttle response down a bit so that we can get more power with better gas mileage. It is a great technology for and everyday car but you will never see any Mcar like the new V8 M3 or V10 M5 and m6 with it because of that lack of throttle response that it gives. all in all i am glad my X5 has Valvetronic but if the M3 came with it i might switch to porsche.