Have a look at aftermarket immobilisers. I have a Pandora Smart Pro v3 fitted to my Alpina. They aren't cheap. It can control the entire car via a mobile app as it connected to Canbus, it has a second fob for immo that is needed to start. It also has lots of sensors that can trigger the alarm, I get a notification if there is a shock detected, and if the shock is hard enough the alarm is triggered and I get a phone call from the car. Also has full 4G tracking and the siren is very very loud
. You can also move the alarm from car to car when you sell it.