Sirius radio problem !!!!!!!?

yeah well i got this letter from sirius saying that the radio exceeds fcc regulations and that i need to correct the connections since i am using my stock radio as the fm pick up for the sirius. i have a 2002 lexus es300 that has been well taken care of and still looks awesome in and out. i don't want to pull the stock radio out until i know that i can connect a sirius fm direct adapter to it. the adapter is simply a disconnect the stock antennae and plug into the adapter and the adapter to the radio antennae input. can this be done and will it give me the best reception without replacing the stock radio since that would cost a bit because it would have to be custom ? i travel often and i always had to pull over to find the right station for clarity usually between every three or four city's which is annoying. what should i do ? also installing anything myself is no problem, it's the custom stuff i dont do.