The AT33PTG cost me then about £400 but is out of production now. The nearest equivalent would be the AT33EV at £530.

The Shelter 5000 lists for about $2200 but it cost me less than $1500 buying from Hong Kong.

The law of diminishing returns applies, combined with my belief that the Dynavector arm extracts considerable performance from all manner of cartridges. You're right about synergy too, it's easy to go astray and quite hard to reverse it sometimes