Hello there

Welcome, Colin. It's great that your vintage Trio is still performing and I certainly wouldn't consign it to history, but as patientot has mentioned, after all this time, the capacitors, and maybe other components will have degraded and possibly be in need of replacement. Also, the phono stages in that amp are only a part of it.

Whatever, I'm certain one of the GS phono stages, which will be dedicated to the task, will be much more satisfactory long term. If in doubt, you can try out one of the pre-built ones in your system via the loaner programme. I made the mistake of going for the basic green power supply (cheapskate!) but having upgraded my Revelation M with the PSU-1, I would urge you not to make the same mistake!

(My only experience of Ortofon is by way of an OM20 many years ago, which I thought a bit thin, but I know there are many who like them.)

If the stylus is brand new, you can upgrade when the stylus wears out. 

A G.S. phono stage will be better than whatever is in that amp probably, especially if that amp has never been serviced. There is a good chance components including electrolytic capacitors inside are operating out of spec by now. That usually happens with a lot of old amps from the 70s that haven't been serviced. 

IMHO the 2M Red is not a very good cartridge. Again, my opinion only but it's one of the worst cartridges I've ever heard. So I think you can do better on that front. 

What phono pre are you using? A G.S. or something else?