Integrated Amp Upgrade-itis hitting....

To me, it doesn’t sound like you know what you are trying to achieve with the amp upgrade, because your only fault with it is "long in the tooth". I would seriously consider bringing it with you to your demo and having the dealer a/b it with whatever you are considering. The 3.2 and the other MF stuff of that era was a good, non-offensive amplifier and you may end up preferring it to what you are considering. I would also consider listening to a better CD player.  That might achieve more in the way of better sound than an amplifier swap.  I think you are wise to enlist the services of a dealer instead of stabbing around in the dark.  They should be happy to do the comparisons for you.  Well, maybe not happy, but they should do it.  

I would suggest a new Bryston 135B SST3. Expensive but a foundation piece that will be good 10 years from now. For a little less the SST2 can still be had as closeouts. I think either would make those Tritons sing. 

chayro, you may very well be right and I will take your advice into consideration. As 90% of my listening is still via cd, an upgrade in source may be the best medicine. I thank you for chiming in!'

I've got a case of upgraditis too, and have been considering a new integrated.  I'd suggest putting the Parasound Halo integrated on your short list.  Stereophile recommends it as an "A" level product.  it has a well regarded dac section as well, so you could use your Marantz as a transport, and let the Halo do the decoding.

It's not cheap, but open box deals can be had at Audio Advisor and Safe Soundhq.  

All seem to be good choices.  I only have real experience with the Marantz.  I had the PM-7005, then the PM-8005 and now the PM-11s3.  All have been great. Kept the PM-8005 for a second system.