Aftermarket stereo hiss and poor FM reception

[RT2012z]

Two days ago I replaced my factory BOSE system in my 370Z with a Kenwood DNX691HD. Two problems now.........one is a constant hiss as soon as the unit is powered up, not engine whine but a hiss as soon as the unit is powered up with no volume on the stereo.

Problem #2 is that I now have poor reception with my FM tuner. There were zero issues with the factory BOSE system that I pulled out so I know its something to do with the Kenwood install.

I live about 45 minutes out of Detroit and reception is terrible for local stations, with some not even able to be received on a channel scan, but gets better the closer I drive to the city. I was in downtown Detroit yesterday and reception was 100% for every station I tuned however when I left I noticed the reception get progressively worse the further away I drove. I have a similar Kenwood deck in my other vehicle with neither of these issues and my uneducated guess is that its something to do with the BOSE amps and speakers.

Can anyone offer any remedies to these problems? Any help would be appreciated, thanks.