Make sure you wired the two voice coils / sides in parallel - red to red, black to black. If you wired them in series it will reduce output - if you cross wired them the output will be cancelled (ask me how I know) Likewise if you only wire one voice coil the output will be much lower. It's mostly going to add deep bass. Try a song called "Death of Love" by James Blake - it should rattle your fillings.Installation was easy and I did not need the harness for my 2024 Turbo. Not sure if I'm hearing much of a difference.