???What's The LEAST Expensive "End Game"Amplifier You've Ever Heard???

Though not an integrated amplifier, I'd throw in the CODA S5.5. 50 WPC pure class A, and more in A/B; 100 amp current capable. An end game solid state amp for me, drives all of my speakers easily (even vintage Infinity RS Kappa 7s).

Doug Dale at CODA found a supply of hard to find "high bandwidth" transistors, and upgraded the S5.5 with those......somewhere mid 2023. I'm not sure why they didn't indicate a different model, like the S5.6 or some such; but it is a great SS amp.

I don't know about end game but I quite like my Gato AMP-150 AE

I am thrilled with my system and my amp is an integrated Primaluna Evo 300 (all tube). The tubes made the difference though. Up front I have two sets of Radiotechniques and 1 set of Brimars. In power I have a set of KT-150s and a set of GE 6L6GCs. With 4 KT-150s I was missing out of quite a bit of "mid range magic" and with for 6L6GCs the mids were a little shouty and didn't have enough power. Mixed they are incredible together. 

Speakers are Volti Rivals.

With the right record/recording/pressing, I truly want no more out of my system. There is always better but I'm more than content with my setup.

I’ll be trying a Class D Audio mini GaN 5 very soon. We will see.

My end game usually only lasts until something new , different and cost effective comes along.

Been running mainly Class D for a number of years.   Currently have more recent Hypex Ncore and older Icepower. 

Class D Audio Mini Gan 5. $800 & fits in your hand. 5 lbs. I own two. Try to beat the sq for 5x the price. Good luck.