I recently just installed my Nismo intakes on my Z and later on figured out the rattling i was hearing, was the CAI heatshield rubbing up against the AC Line. It almost cut a hole clean through it before I caught it unistalled it and made a few cuts. I am still however getting horrible squeaking noises around corners and on uneven surfaces. I pinpointed the squeaking to the ac line because whenever I get up in there and wiggle the damn thing, its the same squeak thats driving me nuts! I just got back from the dealership and they said it was impossible to be loose because it is dirrectly bolted to the engine..