Road Noise A4 S-Line

Just bought 1 year old 2.0TDI S-Line Avant. I would like your thoughts on the road noise form the Low profile tyres especially on motorway driving; it does seem a bit excessive. I have also noticed that there is a noise when the brakes are applied that seems to change depending on the road surface, i.e. it seem to get louder if the road noise is louder. I have continentals 235x40x18 fitted.
Any thoughts or discussion greatly appreciated.
GAC

Thanks for reply Dazmo,
It is just because the car is new to me that I guess I am looking for noises etc. The tone and volume of the noise does change with the condition of the road, i.e. more uneven surface (motorway) then the road noise and the braking noise is louder. On a perfectly flat road with a good surface there is no noise at all.
Thanks,

Hey snap, I had the same problem!
I actually felt the car pull slightly on the road test on country roads. Again perfectly straight on even roads. I asked for the car to be fully checked out before purchase. The Audi dealer re-tested the car on a longish test drive, found nothing, they also physically checked the brakes again nothing, finally they took the car to an MOT station and put it on rolling road for brake efficiency tests, again absolutly fine. Hope this puts your mind to rest.
Cheers
P.S. The brake noise is not there on perfectly even good surface roads, it is completely silent. As the road noise builds up the noise from the brakes builds up also, but I am sure it is just the road surface noise amplfied when the brakes are applied.