I've been wondering if anyone has ever opened up the stock amp from the 2016-2019 Malibu to get a look inside. A photo of the output amp IC chips would show the numbers printed on them. Then you can look up the chip numbers to see what the power output spec is for that model. Most moderate-price audio equipment uses integrated IC output amplifier chips, one for each channel. These are self-contained audio amplifiers that just need low-level input and a power supply. I have looked them up successfully for a number of budget-level stereo's and car stereos. I would guess the stock amp can put out about 10 to 12 watts from 20 to 20,000 Hz into 4 ohms, but that just an educated guess. I'm curious.