As I look through the 2004 Brembo Price guide...
X5 Front
2000> 380x34
2-Piece (8-Piston) 1G1.9002A
$4,295.00 $3,500
X5 Rear
2000> 345x28
2-Piece 2C1.8006A
$2,795.00 $2,300
My guy I get my crap from sells those same parts in the blue price.
He (as well as my research) though shows that it'll probably be a better performance benefit if I went with StopTech, although I've never asked him what prices are for a StopTech setup.
http://www.zeckhausen.com/
Check out that site to get a final pricing from them and see if they can get those prices in blue. They are a sponsor for X5world right now and I bet they'd be willing to work something out.