The Sirius Lexus kit clearly calls for the antenna to be installed on the top of the car across from the big factory antenna. It's identical to the aftermarket Sirius antenna that came with my old S50. Sticks onto the top of the car near the tailgate. This antenna should not be installed inside the car. Odd that the factory installed big rubber antenna on the back left of the car doesnt work for XM or Sirius.