I also recommend James Trikalis (0408443352). He is the head contractor for Brant and Autowatch. He did an awesome job installing an alarm in my R32 with:
3point black wire immobiliser
Siren
Tilt, Jolt, Shock sensors
Cabin motion sensors
Quick track GPS (rings your mobile when alarm sounds and you can control most functions on the car from phone)
I just booked him to install the same + keypad in my R34