seat covers, debadge the car, alarm/immobilizer, club lock (adds seconds to possible theft time), kill switches, removable ecu units (ppl in the US do it that way now), removable steering wheel boss (I would but I need an air bag by law, lol)

there's alot of ways to deter theft, just have to get clever

I have a mate with a vintage hemi who always has the right amount of fuel in it that it can only physically drive 40kms on a tank, lol