Any help would be appreciated. Tried to search and didnt find any common issues.Here are the facts:

-Howling sound coming from the front of car when driving 35mph+. This usually starts when i hit 2.5rpm or so, but it is more speed-dependent than RPM dependent. Still occurs when i take foot off accelerator and cruise. Does NOT occur when reving engine in park/neutral.
-Sound is much easier heard when windows are up. Sound has a note to it and is pulsating (not high pitched, not "wind" sounding.
-Just noticed it after i installed a coupe midpipe (i just had the smaller resonator welded in because all my gaskets were rusted) but like i said, seems to be coming from the front so might be irrelevant?
-Have everything installed that you see in my signature, also did 60K service a few thousand miles ago so hopefully trans fluids are ok.
-i do need to replace my belts but they shouldnt be that bad
-i probably have to replace my tires next season, but again, shouldnt be that bad
-I did a light spot check on my car and made sure there isnt anyting caught somewhere in the wheels or in the front that can make that noise.

So anything else i should check out? I have read that wheel bearings are a common problem (not on g35, but in general.)

Thanks.

 

My guess is either your tires are cupped or you have bad wheel bearings. I had to replace my front tires a couple of months ago for a similar problem. They looked OK with lots of tread, but sounded like a 4X4 rolling down the road. It was embarrassing to drive like that.