I'm not sure what brand I was looking at, but there was a long sequence you had to do to arm it. Something like.. Put on emergency brake, put into Neutral, exit car and use use remote to lock and shut down engine (this guaranteed it was in neutral). Then it would restart via remote. The remote had a much longer range than the factory, something like a 1/4 mile.... Very expensive and had to buy another key.... If you want, I can find out what brand it was, but it sounds like you may already have something in mind?

 

I had a Compustar installed Saturday

e-brake, car in neutral, tap the brakes twice, exit the car. Car shuts off and locks the doors when you close the door :)

1/2 mile range