With only 26,000 km on the beast, a bolt holding the belt tensioner to the V-8 block came loose resulting in the following:

-tensioner bent and seized
-serpentine belt forced off pulleys and against shock tower housing shreading the belt and cutting a groove in the shock tower housing
-power steering line cut
-car came to a shuddering, grinding halt

Thank goodness for GM Roadside Assistance and full Warranty coverage!

Shop time is expected to be ONE WEEK as the bolt that loosened and the tensioner are special order items.

I've never read of this happening on the GXP before, but keep an eye on your belt tensioner!