Sell and refurbish?

I've not heard a 8080 after being refurbished, but I've heard Kenwood Supremes before and after. Good before and great after. With thirty years on it, the caps are way, way past their prime, and that probably accounts for the lack of top-end clarity. Others may have other recs, but "Echowars" over on Audiokarma does outstanding work at a very reasonable price, and he's done hundreds.

I don't think you need to do too much to do better than an entry level type of receiver. I can't comment on the Sansui. The last time I heard a Sansui was in 1974. I heard it a lot. It was owned by the guy in the next dorm room to me in university.

You can be very rational about this. Compare what it would cost to refurbish the Sansui to what it would cost to buy something already current. If it's economical, then it might be a fun thing to do, but don't expect it to have any resale value, so it's a sunk cost.

Also consider selling the receiver and going to separates.

I think you should listen to a few things in your price range at your local store before sinking any money into this. That way you will get a feel for whether it is worth the money to refurbish.

If your current system sounds excellent and you enjoy it, then I think you ought to upgrade to a subwoofer instead. This way you keep that clarity w/the Rotel and improve the bottom end. Your money will be better spent this way. Besides, refurbishing can be quite expensive, if done properly by an experienced technician, and you may only have a very marginal improvement in sonics. Go the sub route and you'll be satified.