I'm in the same boat as you but have a 4.8is... You might want to consider a kit from ECS since it also includes spark plug boots. GBorklu also suggested to change upper timing covers too while you're at it.

BMW E53 X5 N62 4.8L - 11127513194KT - Valve Cover Gasket kit - ES#2765666
BMW E53 X5 N62 4.8L - 11127513195KT - Valve Cover Gasket kit - ES#2765667

Or Genuine BMW

BMW E53 X5 N62 4.8L - 11127513194KT2 - Valve Cover Gasket kit - ES#2765668
BMW E53 X5 N62 4.8L - 11127513195KT2 - Valve Cover Gasket kit - ES#2765669