Huk, I don't know if you are driving a diesel but I am not sure i will completely agree with what you are saying... Don't take me wrong and I am only saying this from experience.... at least my car(sd) rocks up to 200km and not 90 km as you are saying.... and when the second turbo kicks in you don't feel any kind of lag at all at higher rpm....

Now I am thinking that maybe the gasoline will not move faster at higher rpm as you are saying.... why ? lets try to make a more fair comparison x5 3.0si (gasoline) and x5 3.0sd (diesel) both cars are almost the same hp (10hp difference). But there is nothing to compare at lower or higher rpm... with those 2 cars... even if gasoline is faster at higher rpm the diesel will kick its ......