PSB Gold I to NHT Classic Four

Will this be upgarde or downgrade?
Just an educated guess, but I would think it might be different, but not substantially better or worse. If you have the PSB, that's a nice speaker, especially at the price. If you know what you're seeking and the NHT has it, then by all means, go for it, but I doubt it's an upgrade relatively speaking.

These are two of my favorite recommendations for people who want excellent sound without spending a fortune.