I had a look at getting a tracker fitted to my bike as they are so easy to steal, cost was around £300 to be fitted then like another £45 a year for the subscription but my insurance only went down by like £20.
Id say get a quote for fitting and then the year cost every year after, then phone your insurance company and ask them how much you will save.
If you not looking to save money and jus have it as piece of mind as some of the trackers phone you/ text you when the car is moved towed lifted ect then I might be worth it to know your baby is still going to be there in the morning.