I'm a little worried of my new RX-8 walking away seing it will be such a hot item. I know it comes with an engine imobilizer and stock security system, but is there something out there that will deter potential thieves.

I'm looking at things like window etching and the Boomerang system, but I have no feel for value or how much of a deterent it is for thieves and not just your kids going out for a joyride. Jasper also mentioned getting alarm shock sensors as an upgrade to the stock system.

Any thoughts on the stock system or is it worth getting another system.

Order the Alarm Shock Sensor Upgrade and nobody will be stealing yourn car.
Part # 000-8F-K01

In terms of protecting your car, In general, a Club or just a Steering wheel lock is a good addition to your car. Why ? Even though we all know it doesn't take a rocket scientist to figure out how to remove a Club quickly, that is another annoying obstacle the thief will need to remove before he can take your car and the thief knows that. The idea is to send them the message going "if you are going to take this, you might as well take one that is a bit easier". (works the same way as their Home Security Stickers outside your door) :)

We all know if someone is going to steal your car absolutely, there's really little we can do to stop them. The best thing to do is to just let them know it is not going to be a cake walk right up front and hope they will "pass" on your car.

for immobilization I've heard good things about the gadget that attaches to your steering wheel/brake pedal I believe..
If a "pro" wants your car there is not much you can do, but that gadget should be enough to thwart casual joyriders.