i think the best theft detterent for me was keeping my factory HU. lol
earlier this year, someone got into my car at night. but fortunatly didnt steal anything but some loose change and burned cd's, went through my console and glove box, took the time to lay out everything in an orderly fashion on the passenger seat.
all amps/subs..etc are in the trunk. i think they saw my factory HU and flat out assumed i didnt have a system. I think the reason it got broke into may likely be my very dark tinted windows.
i mean if you think about it, alot of people with really dark tinted windows can kinda tell you theres something in there they are hiding from plain view. fancy rims and paint job...etc on top of that i know makes me think they have a system of some sort.
i'm not recommending or nothing, some here may frown on this. but i never lock my car doors anymore. Locks are for honest thieves. years ago i used to until i got my window busted out, it was a hatchback....they literally pulled my factory AM/FM radio (no casette nor cd, just am/fm) and before pulling the wires, they mustve noticed it was crap and threw it back down. they stole a sub box with 2 blown kicker subs in it. lol ....(i just got it for the box off a friend and had it sitting back there till i was ready to put my system in)
so the joke was on them except for the fact that it costed me $200 to get a new window put in. if i didnt lock it, i wouldt have been out anything other than that box that was practically free anyway. but they broke into it cause i stupidly had that box in the hatch and you can see them in plain view when walking by, it i had a trunk no one wouldve bothered as the rest was factory.
so now, i keep my ride as factory looking as possible. Also, if it wasnt mentioned, its a good idea to not do your system installs outside of your garage, kinda obvious to neighbors n all but i'm sure none of you here do that anyway. i try to hide my car best i can when i mess with mine.