I'd hate to be redundant, but everyone else pretty much said what I know and would have said. I work at a best buy, so I know a little about the alarms. We sell clifford but we are not fortunate enough to carry the avantguard 4. From searching around other stores and reading up on information I personally think the avantguard 4 is the best alarm on the market. The viper 800 is pretty close but clifford owns it. Yeah DEI owns both but clifford makes the best alarms out, they are always coming up with diff. security devices. In my opinion do not get a black widow. At least any black widow alarm that best buy carries. Best Buy in general has low to mid end stuff at the most. If you want a good alarm I wouldn't shop there unless you are buying the higher end clifford ones there. Usually the prices of alarms include installation so you might want to keep that in mind(at least at best buy it does). But honestly just because you have an alarm doesn't mean your car is unstealable, so only you can decide how much security you need. Personally I have an avantguard 4 on order and an autolock, just in case you were wondering. Good luck with whatever you do though!!!!!