Here is a little write up on car alarms I found. This guy appears to know what he is talking about.
http://www.vsracing.net/~suspended/
I am researching various alarm systems and so far from all reports the Clifford G5 series has the best overall opinions from people who know alarms.
The Clifford Avantguard G5 is the one I will be putting into my FJ when i get it. Less bells and whistles but more solid security that most. Add a wireless immobilizer and a few other complications and it will be pretty good.
edit> The alarm is only as good as the install so unfortunately a good install will be very labor intensive, ie. expensive. The VIP shouldn’t be that much though, it is mostly plug and play. There are directions available that spell the whole thing out on that reference document site for a DIY.