yeah it's normal, they tell you how high you can "safely" rev the motor before it is totally warmed up, the high-performance audis do this too only theirs are digital. Most BMW M cars have this or something like it (in the new ones there is a dial that moves around the tach instead of lights)

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2006 BMW X5 4.8is Lemans Blue/Beige/Dark Maple
-Nav, Comfort Seats, Heated Steering Wheel,
Rear Airbags, AUX Input
2009 BMW M3 Space Grey/Black/Carbon
-all options