Let me supplement my previous response by also saying that the 805, 804, and 803 are very demanding speakers when it comes to components. You can never good wrong with upgrading your front end components before your speakers, especially when you have speakers as good as the 805s.
The 805 is good enough that you should get the benefit of every component upgrade you make. I am thinking that the 805, the 804, and the 803 probably "max out" at around the same place.
With that Marantz, you are not even close to realizing what the 805 can do with respect to resolution and imaging. Not by a long shot. So you have to figure out what your priorities are. If you want to hear more midrange and high-end information, better stereo imaging, and a more refined sound, your 805 can absolutely do that for you but you need a better amp/preamp or integrated amp. If you are happy with the sound you have now but want deeper bass, the speaker upgrade will do that for you but it would be a parallel move in other respects.
There is no doubt that you should eventually do both, the question is, what kind of improvement are you looking for with your next move?
The rabbit hole gets very deep at this level.
The 805 is good enough that you should get the benefit of every component upgrade you make. I am thinking that the 805, the 804, and the 803 probably "max out" at around the same place.
With that Marantz, you are not even close to realizing what the 805 can do with respect to resolution and imaging. Not by a long shot. So you have to figure out what your priorities are. If you want to hear more midrange and high-end information, better stereo imaging, and a more refined sound, your 805 can absolutely do that for you but you need a better amp/preamp or integrated amp. If you are happy with the sound you have now but want deeper bass, the speaker upgrade will do that for you but it would be a parallel move in other respects.
There is no doubt that you should eventually do both, the question is, what kind of improvement are you looking for with your next move?
The rabbit hole gets very deep at this level.