There's no fool proof way to 100% protect your car from theft. What you can do is just slow them down or deter them as much as possible by using as many protection measures as possible, electronic and mechanical, so not just settle for 1. It's all a game of risk, they want the least risk so we have to increase as much risk as possible to them. The more protection you have the more effort they have to do to beat those, so that will increase the time and therefore their risk relative to other cars that have less protection. Minimum use all these:
- a good alarm
- a good immobilizer, something that has a pass code.
- a good steering lock, one that can wrap/hold the spokes.
- a good pedal lock, separate from the steering lock.
If you want can also use that rim lock like the above.
GPS tracker maybe but I don't think this will deter much coz it doesn't prevent from taking the car but may help you get your car back if stolen.
So by doing all those, hopefully your car will be less attractive compared to other cars hence the thieves will choose other cars instead. Unless you car is just way too good to pass and they just got to have yours then it's just not your luck but the chances of that is slimmer and the thief must really prepare/be very skillful.