Pro-ject arms will also fit the gemoetry, the carbon fibre ones can be had for reasonable money. You can also retain the silver collar and use that to clamp the arm in place, put a better arm in without having to modify any original components in and enjoy it with a much better arm which it really does deserve, keeping the original parts safe somewhere. Even re-plinthing the deck doesn't involve modding the deck itself. I would also recommend a bearing and motor re-lube/clean.