Hmm, when I run my car into a brick wall, the front end gets a little distorted.
You're holding your foot on the brake and therefore locking up one wheel. It's a sign that your rear brakes are actually working to a degree. A limited slip differential will start working like a regular one at a certain point. I wouldn't worry about it.
I would stop doing those type of burnouts, though. You ARE burning out your clutches doing them.
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351W 89 Mustang GT Convertible