'71 Spoiler

A buddy of noticed the '71 style (gull? boomerang?) spoiler on my GTX furiously vibrates up and down at hiway speeds. This is the second wing that does it, I had to replace it a couple of years ago due to stress cracks around the mounts.

The thicker '70 go wing on my Challenger does not.

Is the vibration common, or do I just have a cheapie wing?

Thanks

Does it have the correct reinforcement brackets on the inside of the deck lid?

It's got the correct brackets.

It's vibrating in the center and at the tips.