Yep - a tracker is on the list. I think all you can do is make it difficult for the casual degenerates so they go and look for an easier target. I agree - anyone coming armed with a tow truck or crane is going to have it away anyway.
I'd add that if you leave it in a remote spot to go for a walk up a mountain or something I reckon the risk is more from opportunist break in's than organised vehicle theft. This is more likely from where it is left often, or at home, where it is seen regularly and the theft planned. Mine is parked tight to the garage door with one of the Freelanders tight to the back end. My brother in law lives in a very very nice neighbourhood. Top end Merc with all the security gizzmos. Went outside one morning to find his car on bricks and all four wheels gone. 2nd time now. A colleague had his Disco 4 nicked from outside his house this year. Police reckon they read his key fob from outside the house & told it to switch the car on - just drove it away. Don't know if that's even possible but they disarmed, unlocked & started it without a key in a matter of seconds and 11 high end cars from the same area were nicked in 30 minutes. You are not going to defend against that level of organisation.