whining belt sounding noise at highway speed

harordr

Hey guys i'm looking for some help....my Z is out of warranty and im at 31k miles. At lower speeds (<50ish mph) my Z sounds normal, as in good exhaust noise and motor noise. Once I start to speed up and I am on the highway, i'm getting like a belt whining noise and its to the point where if i'm in 6th gear and give it just a little gas or even if i downshift to 5th to speed up a bit, I dont even hear the exhaust or motor, all I hear is a whining noise and it sounds terrible. Whats weird is that if I go through a puddle it seems to get worse...could this be a really bad wheel bearing issue or does it sound like possibly and intake problem?? Like i said im out of warranty and the dealership wants $120/hr Any help is greatly appreciated!!