Well, it was easily installed in a golf 4, after watching relevant videos on YouTube.
It has been working flawlessly for 1 month. The range of the system is quite large.
The only observation is the build quality of the controls, and the excessive sensitivity of the command buttons, to the point that when I put the keys in my pocket, they often activate by mistake.

10 days that we have been using it flawlessly, it will show in the future. For its price, it is worth it blindly (I installed it myself). Of course, I don't know what theft security it provides (I don't think it's very secure, but I put it in a 20-year-old car that has theft security)