there is a DIY in my sig on push start. It still requires the key to be in the ignition, you just don't have to turn it as far. If I press the button w/ no key, nothing happens.
If you want an alarm anyway, I reccomend stellar. They have a full line of alarms with various security features that work with the factory alarm port and cost less money. All BMWs 92+ are prewired, except for a handful of 92s made in 91.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>