How good are your ears and sensibilities?
There is no sense purchasing a system and speakers which plays beyond what your ears can appreciate. Or what you can distinguish. I have friends who have spent thousands on speakers because they can both hear and appreciate them.
I spend squat because my ears are shot. Big holes in the frequency range, there's no reason for me to get anything beyond stock.
So, make your subjective experience the "parameter". You'll be happier, and probably save money.
Arf