Marc, I think you could get some improvements by isolating tour t/t from the speakers better. As it stands (forgive the pun), vibration from the speaker cabs can transmit to the t/t via the Kallax and colour the sound. And the louder you play the worse it will be. If you can find a nice used wall shelf for the deck that would help, then you can better enjoy the improvements that some different speakers would bring. Also you can experiment with different ways of isolating your speakers/stands from the Kallax.
And if your speakers have to stay on the kallax, they will be quite close to the wall - so probably not speakers with rear-firing ports.
I just dropped in, to see what condition my condition was in
T/T: Inspire Monarch, X200 tonearm, Ortofon Quintet Blue. Phono: Project Tube Box CD: Marantz CD6006 (UK Edition); Amp: Musical Fidelity A5 Integrated.
Speakers: Zu Omen Def, REL T9i subwoofer. Cables: Atlas Equator interconnects, Atlas Hyper 3.0 speaker cables
T'other system:
Echo Dot, Amptastic Mini One,Arcam A75 integrated, Celestion 5's, BK XLS-200 DF
A/V:
LG 55" OLED, Panasonic Blu Ray, Sony a/v amp, MA Radius speakers, REL Storm sub
Forget the past, it's gone. And don't worry about the future, it doesn't exist. There is only NOW.
KICKSTARTER: ENABLING SCAMMERS SINCE 2009