not sure if this is the right forum for this question, my apologies if it's not.

i wonder if someone can help me figure out how different impedance speakers (or cabs) affect the amplifier, speakers, volume, etc...

suppose that you have an amplifier with both an 8 Ohm, and a 16 Ohm output.

let's assume we're using the same speakers in both cabinets, just different impedance versions.

you have once cabinet with two 16 Ohm speakers, wired in parallel.
and another cabinet with two 8 Ohm speakers wired in series.

are there any benefits to either of these speakers setups, is one better than the other, or is there really no difference?

It often depends on the speakers.

For a cab that's rated very close to the output of the amp, I'd wire in series so that if one speaker blows, the cab will cut out and save the other speaker.
For a cab where each speaker can handle at least 75% of the amp's output, I'd wire in parallel. That way in the unlikely event that you blow a speaker, the cab is still usable (won't ruin your gig) and there's less strain on the transformer.

That said, conventional wisdom states that you want to use the highest impedance cab that you have an output jack for, so in this case you'll probably want to use the 16 ohm cab.
Series wiring certainly sounds different than parallel, but it's very difficult to notice without using the same set of speakers, amp, etc.

Simply put, even two of the same manufacture of speaker will probably make more of a difference.

The output tap is another story, no clear cut answer here.

Some say that 16 ohms sounds clearer and more transparent, similar to audio applications, due to all the windings of the output transformer being used, but these are the same people who argue about crystal lattice integrity and maintaining proper humidity for perfect tone.

I can't hear it, and I'm guilty of the whole "tone-quest" thing...

That said, I usually wire to 8, just because more of my amps have an 8 ohm tap than anything else.

And since I prefer 2x12's, I wire parallel.

Other factors are more important, IMHO, and let those factors be your guide.

Which tap to use and which wiring are way less important.