Here is my suggestion but my application is a little larger size than yours, I believe as I have a 2005 X5 4.8is. This is NOT the cheapest solution but is one that I would recommend.
Tires from Tire Rack
Tires 275/40 fronts, 315/35 rear Michelin Latitude Tour HP, $356 front and $378 for the steam rollers in the rear
New chrome ring center caps
New BMW valve stem with those little stainless caps
Follow up note: After a 2,500 mile run to make sure all is OK, here is my report: There is NO tire noise compared to the OE Michelins Latitude Diamaris, rain traction is great, no noticeable handling difference, total confidence up to 135mph, Final thoughts, good choice from OE. Rides like a high-end SAV should.
This X5 has 54k now...
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2005 X5 4.8IS
The
Blue ones are always FASTER....
Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green