I own a automotive aftermarket business that specializes in remote starters and other accessories. We use Directed products that has a retail name "Viper" (fitting isn't it) for all our applications. A Viper remote start can be added to any vehicle with a manual transmission. During the installation, the neutral safety switch is over-ridden, and one of the many wires is hooked up to the park brake. After all connections are made, the system is put into "manual" mode by the installer, and a sequence of events will have to be done by the owner every time before the ignition is shut off after parking. This is called the "reservation" mode.
Here is how it works. Before turning off the car, put it in neutral and set the park brake. Now turn off the ignition, the car actually stays running until you get out and lock the doors using the new aftermarket Viper remote control, then the car dies. Now the system knows the car is in neutral and the brake is set. When ready to remote start just push the button, or now days just use your smartphone to activate the remote start. Here's the cool thing, if anytime the doors are unlocked, before remote starting, the system knows it, and will not let the car be started remotely. It really works well. If you want to check out any of the Viper products, just go to
www.viper.com