I am not sure about your problem... the only advice I CAN give on the topic is NOT to bump in neighborhoods, parking lots, and if you see someone following you DONT go where you park overnight. Currently living boardering the ghetto and knowing many people born and raised deep in the ghetto that is the number 1 rule. If people dont know its there when they can steal it they will be less likely to mess with you, but if you go around bumping your stereo then parking for the night at a buddies place or in the mall parking lot then go inside it takes one wrong person to be informed by the bumping to jack your crap when you leave it unattended. BTW you can give your neighbors my paypal address and they can pay me for their appreciation in talking you into not driving them crazy with your loud tunes any more
Hell, I grew up in a house where whatever I did was in the driveway and I was never worried about anything being stolen... tuning a sub in was done in the driveway, tinkerin with the engine (turbocharged with 3" straight pipe from turbo back) was all done in the driveway, ALL my neighbors knew my car had something reguardless of their car knowledge... now in my current neighborhood I pulled a project car out of the garage so I could pull my jeep in and swap out my sub and amp for some new goodies in privacy away from other eyeballs.
Its not perfect, but I never get bothered *knocks on wood*