That's the limiter you're hitting.
Not too good, since that's high revs. I wouldn't sustain those kind of speeds very long. (Not that I haven't, but...)
a) high revs are harder on the engine
b) it's a lot of prolonged stress on the transaxle
c) it's really dangerous!
It's not that your car can't take it, but it's similar to the stresses of high acceleration, only it's constant.
So it's not good, but nothing will blow up if you do it, provided the car is in great mechanical shape. Just more wear and risk. And danger of getting messed up.
