what to look for in "audiophile" grade parts....

Contemplating an amplification upgrade...what does one look for in regard to audiophile grade parts...for example $500 intergrated vs a $1500 one...I read all this jargon about mosfets,discrete circuitry,fets,o-amps,1% tolerance transisitors,capacitors...what I am getting at is...when upgrading I would like to get not only improved sonics but a lasting design with quality parts...or is all this meaningless and should I be committed now...help me from going mental!
The real question is "what to listen for?"
If you spend more it's more likely better components will be used. I wouldn't buy one amp over another because one states they use 1% tolerant resistors or whatever. The better gear all does. When you spend 1500 on an integrated the build quality, switches and pots will be much better quality.