We had ours installed. Not to thread-jack, but Sirius (or Mazda) sent us incompatible satellite radio parts. Did this happen to anyone else?
We first just headed to Circuit City to take a look at their in-stock Sirius parts and see which was the wrong one, the antenna or the tuner, and they said we were sent an older antenna.
So now I'm sending the old one back, they're sending me the new one, and in the meantime we bought a new antenna (which came with a new tuner, and free installation, so we just had them install it and got it overwith). Now I'll be selling my extra tuner to a friend, and the new antenna -- whenever it comes in...