[Kalenn]

Place a blanket on the spot where the cat lays down. Then sprinkle some cayenne pepper on the blanket. It won't hurt the cat permanently. I seriously doubt it would go back there again. The pepper irritates the pads of their feet and if they sniff it... well... it's gonna burn a little.

I used this method to persuade some cats to leave my landscaping alone. Particularly a lace leaf Japanese maple they loved to dig around. Didn't use the blanket for the landscaping but I figured this would help to save your paint should the animal dig in and jump down suddenly. Plus I don't know if the pepper would do any harm to the finish of the car.