Well, I wouldn't let that be the deciding factor in your purchase...the engine turns fast compared to other cars, but the M103 I6 is extremely smooth, and you don't really feel any vibration or noise from it, for the most part. And even with the gearing I had the car over 110MPH several times, and it felt totally solid...

I just sort of decided that it was designed that way, so it should work just fine.

__________________
Current cars:
2000 ML55 AMG, 174k miles
2003 C240 T-Modell, 202k miles
1995 S320, 207k Miles