Moving up from Marantz 2325, to new amp and preamp

I have lived for years, happily, with my numerous, rebuilt, Marantz 2325's--mated with Castle Speakers, and Oracle Turntable-Cal Audio, CL15

Recently having conversation with audiophiles about improving the power side of equation---suggestion for slightly used Bryston Amp, pre amp--I have no experience with this equipment. I have found some of the modern equipment either "harsh" or lacking the "drive" of my 2325-

trying keep investment at $5000 or below (realistic?)--would welcome your input, re: your suggestions for what might be improvement in sound quality---want to keep sound "warm"---"English"?--Nothing with overly high highs or booming bass--all feedback is welcome--
In my opinion the Bryston ( though a great product ) might not have quite the same sound as your elder Marantz..Quite a difference in sound..I might consider a Top quality new or used Intergrated Tube amp ( many available ) ..I think at least you have a better chance of getting the "Sweetness" you like by going with tubes......Do your homework and gather as much info as you can and go out and listen in Audio shops in you area ......For $5k there are plenty of options out there for you....
you're fine.
Try upgrading your power to the Marnatz 2325 first before getting rid of it. I would suggest that you get a Shunyata Hydra 2 or a MIT Z Duplex Super. See if this gives you the improvement that you are looking for before you spend any real money.
hate to sound like an idiot---since I've been out of the game for a long time--but what are the items your are suggesting--

I am guessing, a second power source to run bi polar to the speakers--

just thought I'd ask----thanks for the input--
Musical Fidelity make nice integrated amps that have the nice
points of tube and solid state.Their power amps are good too,but will increase the cost going separates.I think they
give you a good value,and embarrass pricier amps quite often.
Worth checking into.They should sound more refined.
Etbaby is talking about a power conditioner, not bi-amping. :-)

You already know what I think...Arcam or B&K. Or Cary...but that would have to be used, and you'd have to use separates.