They destroyed your speakers to spite you because they could not get them out. What do you think they will do if they can not get in the car? Is a stereo worth more than sliced tires, keyed paint or broken glass?
Quick story: I once used locking gas caps after a rash of siphonings. Well, the next time around, probaly pissed I used a locking cap, they punctured the fuel tank. It would have been much cheaper and less hassle if they simply stole the gas.
Low life trash will get what they want or destroy what they can't, as you said, just for spite.
