Strange Vibrations that go away

[Fberry]

I've got a 2006 Pilot EXL and have a strang issue i'm looking for some help with.
When we get into the pilot after is has cooled down for the night, it vibrates quite violently from 40-120KPH after about 10Km, the vibrations die down and there is only a slight vibration thru the wheel. You can also hear a wawawawawa sound that is consistent with speed.
I have found that the steering wheel responce is slightly slow, ie. when parked I turn the wheel and I can feel a delay until the wheels get there.
I've had the car aligned at the local honda dealership where they said it had toe out but looked good other than that and I've rotated the tires.
The car has 115000km on it and the tires have 5000km on them.
This vibration issue has been there since I bought the car last year, it's just starting to get annoying so I'd like to fix it.

The brakes have been serviced recently

Any suggestions.
Thanks for the help
Frazer