You could try the Cat Clamp. It actually doesn't completely prevent theft, but it does make for a nice deterrent.
A good thief can cut of your cat. converter in like 20 seconds, so this should help deter them. However, a determined thief will still be able to cut the whole thing off...it just might take a bit longer.
I would definitely recommend this one. You're looking at getting your cat con stolen in a matter of seconds so with this cage (made from aircraft wire) it's nearly impossible to cut through without heavy duty machinery which will also add more time and better chance of getting caught. It's not impossible, of course, but if he/she is a smart thief they'll leave it alone and move on.
This one does look like a great deterrent. It will dramatically lengthen the amount of time it takes to remove the cat. It sucks that there isn't a way to completely secure it!
Here's another option for you to look into.
Like Doug said, these are not completely thief-proof. Honestly, my mechanic said they can be cut through rather easily. It will, however, make the thief's job a lot more difficult and will take them longer to cut it all off, which is usually deterrent enough. See, in the world of thievery it's all about speed! You gotta be in and out quickly so no one will see you. If they have to spend an extra minute or two cutting off all the extra metal it might be enough to make them move on to the next car instead. Sucks to be them, but they should have known better.
Get one of these and a good alarm system and you should be in good shape.
This is a decent device. Not thief-proof though!
I think you should get a dog. They will always let you know when something is not right! You can get one from the pound and it will be cheaper than the Catlock!
I would say the best thing you can do is etch your vin number into the converter in addition to buying a protector, so if it gets stolen you have a chance at retrieving it.
Good point. I guess it's possible to retrieve one if you have your VIN on there.
You know, I'm equally angry at the guy at the scrap metal yard who is buying all these cat converters from people that are obviously stolen!!! He's the enabler in all of this mess!