(1) I would suggest that you actually test-drive the Marantz with a list of contenders and the all-too-many pretenders. I had the DYNACO A25s with the MARANTZ before I upgraded to the JBL L100’s. Their performance (or lack thereof ) was the driving reason for the change.
And the degree of audio performance improvement was epic .... The DYNACOs were comparative crap
(2) having said that, today’s bookshelves with their vastly improved designs, superior parts components, and now properly designed cross-overs unavailable back then, will generally smoke all of the "vintage" kit performance wise ... It's Not even close. ... Even today's budget kit would be my first choice over "vintage". The old stuff will also need surround replacement, cap replacements, generally have scraped cabinet finishes to boot ....
As has been said repeatedly to date, "vintage" in audio is not "vintage" in wines. In audio, it just means "old technology " and these are limited performance kit that are also failing units as they age.
i can understand a subjective yen for nostalgia kit reminiscent of one's youth .... Fine .... Enjoy .... But if it's maxing out performance, look elsewhere.