If anyone has ever taken the paneling off around the shifter (which I guess is common in manual Z's), they probably messed with the little sound shield that goes on the base of the shifter. I haven't bothered to fix mine yet (it's just a little noise), but if the noise shield thing that goes around the base of the shifter is put on wrong, 2nd and 4th will be loud while 1,3 and 5th will sound normal. You can check this by cupping your hand around the back side of the shifter at the base. If the noise level is significantly reduced, you just need to turn that noise shield thingy back around 180 degrees so that it's on right. Again, I've only read about this (a lot of reading though) and have not done it myself, so I could be wrong ... Caveat Emptor.