Thanks for the response guys.

I have the original rims on my car with farily new Hankook tyres. My 06 XF has done 60,000 kms (~38,00 miles). It sounds like I have exactly the same noise issue at ~ 30 - 45mph. I thought it was the tyres to start with, however the noise has gotten progressivly worse over the past few months and it sounds like an oscolating grinding noise which I wouldnt expect from tyres. I also have the minor shake at high speed (enough to be anoying).

I took it to a tyre shop last week to see if wheel balancing or the tyres was the cause of these problems, however I was told both are in good shape.

I will replace the steering stabilizer (thanks for the tip).

I am thinking it has something to do with the brakes or the uni-joints. I'll keep at it and let you know how I go.

Cheers,

Brett.