Has anyone self-installed a Sirius radio package from BMW? I have a pre-wired 2006 X3. The dealer told me it would cost $910 plus tax to install the Sirius package. I can buy the necessary parts for under $500 (the e83 package from Circle BMW - http://www.circlebmw.com/parts/sirius/sirius-e83.htm) and was thinking of self-installing.

Is it difficult? Any tips? I am moderately handy.

Thanks