I think Nrchy's car analog is a little misleading. Hi-end audio isn't a comparison between a Passat and a Jaguar, instead it's the difference between a Lexus 430 ($55,000) and a Mercedes CL55 AMG ($120,500). A well put together $15-20,000 system is like the Lexus and they are truly excellent, luxury oriented products. The M/B AMG at twice the price offers offers a little something that the Lexus doesn't, but I would be reluctant to call it superior performance. $75,000+ stereos are like that Mercedes. I think it's more a pride of ownership type thing and there's nothing wrong with that. I could be wrong, it's just my opinion.
Hey, if you don't like the earlier Harbeth based system I proposed, then consider this one:
Speakers: Vandersteen 5s
Amp: Berning ZH270
CD: Sony XA777ES or Gamut
allocated $2,500 for cables and stands
This system lists for $20,000. It goes real loud, goes way deep and offers SOTA soundstaging. You can pay multiples more, but are you really going to make a "huge" upgrade over it's quality?