Wanting to know how many amps the stock unit put out per channel?

 

Here's a good explanation I found about the stock amp which is rated at 368 watts total:

368 watts is wildly misleading. There are a 3-4 or so ways to rate watts out of an amplifier and only one of them is factual and not misleading. Many manufacturers like to use the most lenient rating which is peak music power which is what it can put out for brief intervals like a bass note that is brief. Like you may be able to push a heavy truck for a couple feet using all your strength but you wouldn't be able to keep it up for long.

That 368 watts is for all channels and is the "music power rating"... so first divide it by five for the five channels... that's 74 watts per channel. Then divide that by four to get an approximation of its actual RMS per channel which is more like 18 watts per channel. That's not an exact calculation but most audio/electronics person will agree with that very close approximation. And 18 watts per channel is likely a little generous, most aftermarket radios are lucky to get 12-14 RMS watts per channel.