I use a codealarm and have used their products for years. The range isn't the greatest but my friend sells them and installs them for free so for around 200.00 I can't complain. It also turns on your headlights independently. You can hook up the factory alarm so that it arms and disarms with the aftermarket alarm but you have to know how to do it. For the ultimate my friend sells a satellite unit which allows you to track your car from the internet. You can also start your car anywhere even across the US because it is all satellite accessed. Good way to keep track of were your children and spouse
are at any time. It is a subscription service so you can also have the company unlock your doors if you left the key in it. You can also shut down your vehicle if it is being driven without your consent. Pretty cool stuff but I am too cheap for the monthly fees.