Not exactly 100% relevant to your situation but I did replace the stock stylus on a Grado Black with an 8MZ. It was an improvement. At the time, for unknown reasons, the 8MZ was priced lower than a Grado Gold replacement stylus. I believe prices of 8MZ and Gold replacement styli are now the same. Some claim the 8MZ is better than the current Gold stylus. I can't speak to that but see comments on Needle Doctor.
Grado Stylus Upgrade
I currently am using a Grado Gold cartridge from the Prestige line. The cartridge was bought new about a year ago and has not seen heavy use. Basically, still like new. Although the Gold is not anywhere near the top of Grado's line of cartridges it is still decent with my system. I have read numerous forums and almost all Grado users recommend upgrading the standard Gold stylus to the 8MZ stylus for superior performance. That stylus goes for $150 which is more than half of what the Gold cartridge with standard stylus costs. I am not interested in a complete cartridge upgrade at this time but am curious if the 8MZ stylus upgrade is worth the expense? I guess that any users that have this cartridge and have done the stylus upgrade consider it a worthwhile upgrade.