my sunroof makes a groaning noise too. i got lazy though and just decided to deal with it.
however, i recently got some repairs done that required them to mess around with the roof and now when i go faster than 45 mph with the sunroof open, it makes a really loud bass-like noise...which i don't think i can just deal with. i figured out that it's caused by the vibrations of this bar that runs across the front cuz when i put my hand on it, the noise stops. i wonder if there is a way to fix that without having to take my car back to the repair shop. maybe tighten something?