SatRadio fm modulator Problems/questions

Backgound: I just installed a Jensen Sirius satellite radio receiver in my
2003 Accord Coupe EX 6 spd MT (incredibly fine car, btw). I need to turn
the volume on the stereo to the very top to get a reasonable amount of
volume for the SatRadio(note 180 watt stereo on this model). However, when
using the CD or the radio with sat off, 2/3 volume is plenty. To add insult
to injury, there is a good deal of background noise when the volume is
turned to the maximum, especially noticable on the talk shows. This noise
is still present with the car turned off, the ignition turned to accessory,
and the volume all the way up. The noise disappears at lower volume levels
so I am assuming it is coming from the amp with volume turned to max.

My question: how can i get good, clean sound with sufficient volume
(e.g., is there an in-line booster amp i can install just for the
modulated system - or another amplified approach, for that matter?)

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