The Crossfire has a brake pad wear sensor that will illuminate a light on the dashboard when the pads need to be replaced. As far as the squeak goes, here is what the service manual says:

Brake squeak or squeal may be due to linings that are wet or contaminated with brake fluid, grease or oil. Glazed linings and rotors can also contribute to squeak, Dirt or foreign material embedded in the brake lining will also cause brake squeal.

A very loud squeak or squeal is frequently a sign of severely worn brake lining. If the lining has worn through the brake shoes in spots, metal-to-metal contact occurs. If the condition is allowed to continue, rotors may become so scored that replacement is necessary.