I run the 295/40s. I did this on my '02 4.4i as well. I prefer the look, personally (for a view of my former X5, check out the post on the front page of X5World at
http://www.xoutpost.com/articles/x3/w...mw-wheels.html and scroll down for the picture of the Steel Grey 4.4i).
I just did this same upgrade to my '04 3.0i, even using the same Goodyear RSA tires (which I have had great luck with), except I went with the Style 132 20" reps that I felt were a better match for my facelift X5 than the Style 87s.
IMO, the 315 rear/275 front tire sizes on the OEM-style 20" wheels look too overdone on a non-4.6/4.8 fenderlipped X5, while the 295s pair nicely with the staggered wheel sizes and still very much give the staggered look. Believe me, there is NO mistaking the stagger! The 295s give the front tires a little more "fill" for the front fenderwells while reducing slightly the "steamroller" appearance of the 315mm rears. The car feels a little better balanced front to rear with the 295s in terms of braking and handling. Finally, the 295s do not extend out of the fenderwells front or rear, which means you're not throwing road crap up onto your paint.
Everyone has their own preferences and these happen to be mine. Bottom line - the 295s work out just fine.