Theres a vendor over on the 350 site selling Zenesis alarms. The 502 has a LCD remote, remote starter, alarm, shock sensors, and a special tool called the z-pass that sticks to your window and if you lock your keys in the car or loose them you can enter in a code on the keypad to unlock the car.
Zenesis Alarm Systems now sold by Import Image! read inside! - MY350Z.COM Forums
Website to the alarm
Import Image Racing: Zenesis ZN-502 Alarm System