Amp - preamp or integrated

First thing is keep in mind that there are integrated amps that are designed as separate amp and preamp within one cabinet. If you go with an integrated amp, put that high on your list. I’ve leveraged that with my two NAD integrated amps wired to bi-amp my speakers. Your choices of configuration are just as unlimited as with separate amp(s) and preamp. 

First, I estimate that my budget for new amp /pre amp or integrated will be around 5K after selling my Rogue Chronus Mag 2.  McIntosh would be out of range unless I get a good deal on used ones. 
My Rogue integrated although 4 yrs old, the tubes have low hrs. I barely put 10- 15 hrs per month. Short of 10k hrs they claim to last. Adding a subwoofer was brought up in this thread also. 

Preamp Audio-gd Master 1. About 2k shippment included. Someone compared it with some much more expensive Krell preamp saying the M1 blew it out of the water. Some others believe it can easily compete with preamps costing 3 to 4 times its price. Look for it on Internet. 

Class D Power Amp Nord Stereo SE (dual mono) with Rev D boards. About 2.5k shippment included. Someones compared it with amps costing 50k or more. Look for it on Internet. 

Hulgich Audio won the best sounding stand award in the Melbourne Hifi Show in 2017 and second place in 2018, with Nord amps and an Audio-gd DAC, competing against systems costing up to 500k. And the Nord amp used had Rev C boards, not the Rev D ones. Ive had both and Rev D is much better.

Do your research. You can have a 4.5k preamp-amp combination that can easily compete with multi thousands systems. You wont regret it. 

Im sorry, the Audio-gd Master 1 will cost you about 1.5k if you buy it from Audio-gd website directly. 
M1 + Nord = about 4k, a HiFi steal

Lobinero, for me,i would always a integrate amp.: I had Esoteric F0-5 (nice stuff) but it missed in the depht. Mid and high were clear. Before i had Esoteric ,i used Perreaux 250i , Unison research 845...still good apms but always the same problem :Problems with low, for the rest oké .
Till my best friend Tom arrived with the Audio Note M5, preamp, and the GamuT D200. The sound was brilliant: a very good representation of high,mid and low. Also more holographic. Low was better dan with the integrate’s. He showed me,the difference between an integrate an pre/power. If you read reviews of integrate amps like: dan D’Agostini, Dartzeel...;;the same problems with low. But thaks to Tom, i was in the 7th heaven. And connected to “his” Ilumnia Magister . Great!!!!