Exhaust causing a Rattle!!!

I recently put SLP Loudmouth on my 95 z28 and I love it, its great. But the only problem is that the rear hatch now rattles when you hit the gas. Does anyone know what is causing the rattle, or even better, know how I can fix it?

Your stricker might be a little worn, try wrapping a little electrical tape around it and see if that helps.