The Z's odometer is one of the easier ones to turn back. I take it your verification is based on the onboard instrument cluster in the front clip? Not really a verification of any sort as almost all odometers on imported JDM Z stuff (whole cars and clips) are compromised. As Bernie said, you're still playing a crapshoot. I'd seriously consider inspecting the internals before install and purchasing the 100K maintenace parts as a starter.