Doesnt resistance mean same as impedance??

jjss48 and Erik were guiding you. 

You just need to pay attention. When you post the same question twice it make thing even more confusing

And still the world is confused.  So elusive is impedance.  The fog of war. Confusion. No one wins. 
 

big words. Big toys for da boys. 
 

good luck matching components.  Mktg confusion. 
 

Troll.

Prefer great minds guide me.

I know where you're coming from. Had the same problem as a kid trying to understand cars, how the engine runs, etc. All the other kids seemed so well versed. Wasn't until I got a shop manual and did my own tune ups that I came to realize they were bantering jargon back and forth not really understanding a GD thing.

The more things change, the more they stay the same.

Resistance and impedance are the same in that both describe opposition to the flow of current. The main difference is that resistance depends only on the material and its dimensions, and temperature. Almost all electrical theory is just that, theory, and so with resistance we are dealing with an imaginary "ideal" conductor. So keep that in mind and don't be bamboozled when people try and baffle you with BS. 

Resistance then is opposition to flow of current. What about impedance? With resistance we are talking a steady state. But with music we do not have a steady state. Never. It is not a steady flow, it is constantly changing. Every time it changes there is opposition to the change. The amount of this type of opposition is no longer just down to materials, dimensions and temperature. This opposition to change varies with frequency. So we have two different yet related things going on at the same time- the resistance to current, and the way the conductor reacts to changes in current. Which is called, guess what? Reactance! 

Impedance includes both resistance and reactance.

So not a troll after all, but just a guy with a good question. Hope this clears it up.

No one can make you feel less confused if you aren't in the habit of learning and doing a little math.

To make this as simple as possible, impedance usually varies by frequency.  Resistance does not.  So no, you may  not substitute one for the other.  Take a lookt at the Stereophile speaker measurements to understand this better.

When it comes to speakers, 4 or 8 Ohms is usually literally an eyeball average.  At best you may be lucky to get the minimum impedance of a speaker as well.