Akebono Ceramic Pads and PBR / Axxis Ceramic Pads are two of the most popular options for the X5. They produce a lot less dust than the stock pads. For rotors Brembo makes a high quality replacement rotor for the X5 that we have not had any complaints on.
We actually have RPS (Rotor Pad Sensor) kits available for the X5
HERE on our site. Makes getting new brakes easy as it's a one stop shop.
ECS Tuning