I would recommend going with any DEI (Directed Electronics Inc) alarm, which includes the following brands, Viper, Python, Clifford, Avital and a few more. I would stay away from Audiovox. I have not heard of Compustar. I would recommend the Viper 560XV alarm with autostart. I believe one can be installed for around $350-$400. No pager with it though.
The key to a good working alarm is in the installation quality. If there are poor connections your car might false alarm in the middle of the night or not even start. I would have it installed by an authorized dealer because most alarms bought from an authorized dealer will come with a lifetime warranty, which comes in handy if there are any problems. It's usually hard to get a Joe Blow installer to attend to a problem in a timely fashion if you ever have a problem. Plus he/she might want more money to fix a problem that should have not been there in the first place. I have used DEI products for at least 10 years and have great luck with them.
As far as the pagers go, I once had a pager also and found out I really didn't need/want it. I'm not the type to want to encounter some thiefs in the middle of the night one-on-one. I suppose if you live in an area where you can't hear the alarm sounding you might be able to call the police if your pager goes off, but I would only call if you are positive it isn't a flase alarm. Alarms WILL false every now and then (Thunder, loud motorcycle/car exhaust etc) A professional installer should tape all the wires up under the dash and hood to make it look like stock wiring and hide the siren as best as possible. A thief would not stick around long if they have a hard time de-activating an alarm. If a PROFESSIONAL thief wants something in your car, he will get it even with an alarm or pager. A pager can't hurt though, so if having one makes you more comfortable, then go for it. But I would make sure to have a good alarm, with the pager system installed separatly.