Much better MM cartridge than Shure V15 IV?

You're already there,save your money or stick in Red Kettle if you just want to be rid of it.

It's good to get opinions as to the wisdom of further investment. I was wondering how close I am to diminishing returns and you guys have helped clarify that. The phono amp investment seems to be a path I can take. I like this system a lot, so maybe pristine vinyl purchases might be a better investment!

Stirling has recently released AB-2 bass units to match their LS3/5as. They are not yet available in the US but can be ordered from the UK. That might be a reasonably sensible way to increase the scale of my sound in my smallish listening room?

Smart,of course ALL Bruckner fans are !

Good idea...get a few hi grade vinyl releases before anything major...a tube phono pre would be nice addition...the more I think of it...there is nothing blaringly wrong with your system...a sub would add oomph but dont expect miracles

Phasecorrect, thanks for affirming my choices so far. Clean vinyl ....yum!

Your point about subs interests me. The matching LS3/5a bass units sit underneath each speaker and act as a speaker stand. As far as I understand the specs, they dig about 20HZ deeper than the speakers alone, down to 50HZ max. Is that a very light addition to the bass response of my speakers? The cost is quite high: $1500 to have the units purchased and shipped to the USA. Does that seem like money well spent? Phono amp a better idea?
Thanks