How can improve the quality of my Sirius Radio?

I recently purchased a Sirius Stratus 6 Dock-and-Play Radio and installed it in my car. unfortunately I can only use te fm transmitter. The problem is that there are some stations that work ok, but there is still a consistent fuzz. I was wondering if it is the radio itself or I need a stronger fm transmitter. Help is much appreciated. Best Answer gets the Points!

The FM transmitters in those SUCK.

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