I would contend that the SR80 are the sweet spot in the Grado range. 325's may offer a little more of what I want from Grado but the wretched foam cups, weight distribution and, well, weight make them unpleasant after less than one album of listening time. The more expensive versions... nah, not worth it.
If you can live with the egos, the best upgrade for the '80s is a better signal chain. They are very capable (for their money and some way above it). Mine are over twenty years old, never had an issue with them (excepting the foam ear pads of course - on my fourth pair of Grado originals).
Not cosy for sure, in sound or comfort, but sonically very capable of revealing what's going on upsteam.