Tuner or Receiver


I'll preface my main point and question by saying that I recently bought a used Yamaha RX 596 Receiver which is around 15 years old.  After biwiring my Castle Conway 3 Towers to it, I have been blown away by the sound from this system.  Far better than any previous amp I've used with these speakers and probably due to the 85 wpc vs 60 wpc or less and only using a single speaker cable for each.  


This leads me to the question about tuners and receivers.  Currently I have a Carver TX11a and also a Onkyo T-4310r.  Both are quite old but still work fine.  But...  Has recent tuner technology advanced beyond the the units from the 80's and 90's?  Is the sensitivity of the AM and FM sections superior these days and is the selectivity also better?  I don't need Digital FM and still listen to analog AM and FM.  Just want to know if I would be better off with a new tuner or receiver that would offer better audio quality or better signal capturing ability?  The tuner in the RX 596 is OK but also dates to about the same time as the Onkyo tuner.  Onkyo seems better too.
will62
Look up the Tuner Information Center....  http://www.fmtunerinfo.com/index.html#audiophile
and you will have subjective sonic results of lots of tuners..  Based on extensive reading I acquired a near 45 year old Sansui TU-9900 fully modified by Mike @ Radio X.  It blew three CD players out of the room until I got a Sony XA 5400 ES which was/is a Class A rated Stereophile component.  There are some very highly rated old tuners that can be had for a couple hundred and then modified later when finances allow.
My only concern with buying older gear now is the potential for a failure of some kind and not being able to have it repaired.  Unless the new Tuner technology is superior to that of my Carver or Onkyo I will likely just stay with them.  They work well and do a good job of pulling in weak stations on FM.  And the audio quality on both is good.