install a cat shield aka a plate that covers your cat. Mine got stolen, a shield was $350, they totaled the car for over $3500 by taking the cat if I would have fixed it due to fucking up the exhaust pipes and o2 sensor.
Shield is only a possible time-lengthening deterrent. I installed one and my cat was still stolen. I can't say how many attempts it deterred in the mean time, if at all.