What to do with the stock V5 speaker? Now I hope you aren’t going to sell it to someone so why not use it as a testing load for the amplifier. I put one of those cheep ¼ inch cables on it packed some fiberglass around it and put it in the box the amp came in. So now instead of just looking at the output with a resistor as a load I have a speaker instead. There is quite a difference in the waveforms on the scope between the resistor and the speaker. With a square wave you can see overshoot with the speaker you do not see with a resistor. Also you won’t drive everyone crazy (cats, dogs and neighbors)