[roughyear]

I was behind an X7 this morning and noticed that both rear wheels were tilted inwards (at the top)? Is this normal or manually adjusted to get the negative camber?

I thought this was a sign of a bad suspension/etc ?

[Ninefourteener]

Not necessarily. As the vehicle lowers, the camber will be increased. The vehicle may have been lowered a bit.

Camber by itself doesn't necessarily prematurely wear tires.

So long as the wheels are straight and true, it will actually help the car handle curves better.

"Toe" however, is far more important. If the toe setting is off even a few degrees, you can chew up a set of tires in under 1000 miles.