I ended up placing a rubber pad between the top and side spoilers and tightening all the screws. That got rid of the creaking noises.

 

Thanks for your reply, I removed the spoiler today and got rid of the creaking, unfortunately the noise is still there.

 

I have also a very nasty Crack/ticking sound wich seems to come from drivers side upper tailgate area. Can’t find it also. Have cleared already all the plastic from the tailgate, and even replaced the motors and the automatic lock. Noise still there. It’s driving me crazy!

 

I have put some foam tape on the inside of the trunk where it comes in contact with the boot strut as it closes. The noise has not been there for a while.