nasaman OP
Vitus versus Gryphon
Your SF’s have an evil load right through the bass
Stereophile: The speaker is still a demanding load for the partnering amplifier, with an impedance magnitude that drops to 2.5 ohms throughout the upper bass (fig.1). There is also a punishing combination of 4 ohms magnitude and –50 ° electrical phase angle at 70Hz that will suck gobs of current from the amplifier.https://www.stereophile.com/images/archivesart/1207SFEfig01.jpgT
I don’t know about the Vitus as nowhere, does it state what it can do wattage wise on the bench into 8 4 then 2ohms loads, and if it’s Bi-polar output or Mosfet, it’s an unknown especially into these magic speakers of yours if driven right.
With the Gryphon’s you know your getting an amp that will breath easy into 2ohms all day, and that’s because it’s bi-polar output huge power supply and very well designed.
Your speaker at 90db will love the Diablo 120 or even better the Diablo 300. And they sound just like what you said you like you sound to be.
https://gryphon-audio.dk/shop/integrated-amplifiers/gryphon-diablo-300-integrated-amplifier/
Cheers George