I tested the antenna using a Business Radio from a 1997 BMW in the basement of my house. Not a good place for reception. A standard dipole barely picked up any stations.
The amplified antenna really surprised me at how strong the reception is. However, powering it with 12V or not barely makes a difference. It helps, but just noticeable. The performance is great either way.
The adhesive pad it comes with is really strong. It also has clips to route the coax.
I'd recommend it highly.