Audio Research VSi55 Tube Rolling

I've got a VSi55, and would like some tube recommendations...rather than start a whole new thread, let's resurrect this thread after an 8 year hibernation...

Lots has happened since 2006...KT120s have been introduced to the mix (and fully compatible with the VSi55), and the KT150 (about which ARC is still mum regarding compatibility, and I have followed the other KT150 threads here but didn't want to hijack them), and I think the introduction of the reissue Gold Lion KT88s is a relatively new thing as well.

Has anyone done A/B comparisons between the 6550WE and/or the 6550 Winged C vs. KT120? Or maybe found a newer KT88 variant they liked better than anything else?

My VSi55 is in a smallish living room, powering a pair of Proac D2, and I listen to everything but country...from 80s rock to bossa nova to Charlie Haden to Yo Yo Ma, so I'd prefer a tube with a balanced presentation (rather than one that favors midrange presentation, for example).

Thanks in advance!

Hifigeek1, thanks for the input - I have seen mention of the quality decline elsewhere, so I'm on board with what you're saying.

Albertporter, I've already confirmed with ARC (and others have posted previously to the same effect) - the VSi55 takes the KT120 no problem. No word yet on the KT150, but the 120 is a go.

I'll probably go with the KT120 and see how they compare.