the first month that I had my civic I got my stereo stolen, only had a HU at that time so that's all they got (and the change in my ashtray)
so then I got a new HU and a sub/amp/new speakers and made a "decoy"
I took the faceplat and all the knobs and buttons off of the tape deck that came with my car and hot glued them to a piece of black card and put that in the DIN slot and never had any probs for the rest of the summer
now I have a cheap ass Car-pro, it wouldn't stop anyone really but it controls my power locks and that is the main reason I have it, plus it makes a fun noise when I arm/disarm it
also, if you have a teg with round headlights it will get stolen. all of my friends that have ever owned one haven't owned it for long. most of them didn't even upgrade the stereo... bone stock and the car would get ripped off and found a few days later stripped from top to bottom
I still cross my fingers every time I walk away from my car, it is one of the worst things to have your car broken into and I don't wish it on anyone
Sean