How a manufacture calculates(or, misrepresents) their power is meaningless in terms of sound quality. It is nothing more than how much power is there.
Your speakers themselves determine 90% of everything sound related.
It also helps to know how power and volume work. As "total power" is...
The "ohm range" is not a user selectable thing. It is based on the speakers.
Also ohm load is not a constant. It could be 4ohm at 150hz and 12ohm at 10k.