I just took my 03 in for a courtesy 100 point inspection, and they found 2 problems. 1 being aging cracked belts, and 2 being my lower shift boot (rubber) is torn, hanging down and making contact with the driveshaft, causing vibration through the shifter at high speeds.
They want $20 for the lower shift boot and $85 to install it. And the belts with install will come to $181. They showed me the torn shift boot, and it will require removing the shifter to install, so I gunna let them do that. But I think that ill change the belts myself. I just read the manual and it seems easy to do, just a matter of getting the tension to correct specs without a tension gauge. I dont know the cost of the belts alone, but I gotta think that Most of the $181 is installation cost.

 

Should be $80 or so including the belts.

 

It would take about ½ hour to install belts. They cost around $25 for the pair IIRC. If you do it yourself, make sure you don't overtighten them or you'll wear out the bearing in the idlers. Make sure you tighten the lock nuts on the idlers but don't overtighten them or they will deform or bind. Leave them too loose and the nuts will come off along with the idler pulley.

Here's a DIY: https://my350z.com/forum/engine-driv...very-easy.html