2003 Outback brakes, suspension and exhaust.

Hi,

I have a 2003 Outback (4wd, 4cyl) and I have a little bit of experience working on various cars. First of all I'm replacing the front brake pads and rotors. I'm just curious if the rotors are knock-off or are they pressed onto the hub?

And while I'm in there I was thinking of replacing the front struts, is there anything tricky about replacing these or is it pretty straight forward? Any specialty tools required?

My second and more difficult questions is about the exhaust. I have a whistling noise that comes through the exhaust that you can only hear when you floor the car (like getting on the highways or up a steep hill). I had the car in the dealership and they replaced the Cat Converter and it wasn't that. They could not figure it out. It seems to be something inside the exhaust that is making the noise. Any thoughts of what it could be?

Thanks so much!
Rusty