When I added comfort seats from a later E53 to my 2001 X5, I found that the seat belt recptacles with the comfort seats wouldn't work with the buckles in the truck. You can replace the buckle to match the seat, or you can take the receptacles from your old seat and switch them to the new seat. I switch the receptacles from the old seats and everything is fine.

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2006 Infiniti G35
2001 BMW 3.0I E53 X5 Build date 08/2000 SOLD
Lotus Europa 1970 Destroyed by fire
Lotus Europa 1970 S2 Renault Powered
Lotus Type 52 1970 Twincam Webers Powered
PORSCHE 911 Targa 1982 The Garage Queen
Audi Avant donated to Kars for Kids
BMW 525IT Sold
Audi 4000CS Quattro Sold
Jensen Healey Lotus Powered Sold
Opel 1900 Sold
Triumph Spitfire 1971 Sold
Triumph Spitfire 1968 Sold
Plymouth "Cuda" 340 Six pack SOLD