Car Alarms: 2007 Maxima, shock sensor, intelligent key

Question
I'm about to purchase a 2007 Maxima. As you probably know, it has the "intelligent key".I would like to install a system that upgrades the factory alarm and allow me to use the factory keyfobs.Also i would like to install a GPS system such as the Viper 210V.What exactly would you suggest as an adequate security system?

Answer
This is really a question asking for opinion.  I prefer the DEI stuff over all others.  If you ask someone else they may tell you that the Audiovox (Prestige) product is the best and even another yet may tell you that they like Compustar.  What I strongly recommend is going to a local shop and discussing this with the shop directly to ensure you get everything you want in the system.  Talking with the people at the front counter will normally be a good indicator about the competency of the people in the back.  The system you are inquiring about is pretty pricey so I would want to feel as comfortable as possible with the shop before letting them take on the job.

With that being said...the new DEI SST systems include all of the significant security features such as shock sensor, door trigger, etc. But have up to a 1-mile operating range between the 2-way transmitter and the vehicle.  

As far as 'adequate' I sum up all alarms as this:  I do not ever want to hear it go off unless someone is really messing with the vehicle.  An alarm that goes off regularly will be quickly ignored.  In all fairness to other products on the market the reliability of the system is dependent more on the quality of the installation than the quality of the product.  Do your research, and ask as many questions as you can until you are comfortable with your decision.