I purchased an 07 Maxima with the upgraded Bose system this past August. Immediately after picking it up, I noticed that there is a constant hissing noise emminating from all 8 speakers when the stereo is on and in any mode (CD, radio, satelite radio). It is a constant noise that does not variate with engine speed, etc. The noise is most noticeable if you toggle between mute and level 1 of the volume. It is a fairly low level noise, but is very distracting when listening to music that has quite areas in it. The noise kind of sounds like a "white noise" hiss. I have tried modifying every adjustment I can find- the balance, fade, bass, treble, speed sensitive settings- nothing helps. The noise is always constant and always there- from all eight speakers evenly. It even shows up when the stereo is turned off, although it is much less noticeable. I have taken it to two different dealers for a diagnosis. Both concluded that it is normal for the system and let me sit in identical Maximas on the lot- indeed, they did have the same noise. Incidentally, one of them showed me a car with a base system that didn't have the noise. Needless to say, I am _very_ dissappointed in the performance of the system. I feel like I paid extra for an upgraded system that sounds worse then the base system. IMO, any decent stereo should be nearly silent unless there is music playing. I have also tried calling Nissan Costumer "Care" and Bose directly to try an remedy the problem- both avenues where a waiste of time as I can't even get anyone to return my repeated phone calls.
Has anyone else heard of or experienced this problem with their factory installed Bose system? Is there anyway to eliminate the noise I am hearing? Seems to me like a bad ground or something, but I don't know enough about how the system is installed to know how to check much of anything.

I can't say I am really impressed with the system otherwise either- its not very stronge and does not have the best bass in the world. As a last resort, how feasible is it to replace the system- or atleast upgrade a portion of it for better sound quality? I ask since the HU is interlaced with the climate control read-outs- its not like you can buy any aftermarket HU and just stick it in there. I guess I am wondering how to go about the whole process if I am wanting to improve the system. Is it incredibly difficult or expensive based on the current setup?

Thanks for any input.