Even a car stereo with an external amp likely has speakers with lightweight cheap speakers with small magnets and flexi cones. Which are designed for high sensitivity and efficiency at the expense of linearity and distortion. Every OEM is building to a price point first. My bose 10" in-door woofers weigh less than the 6.5" mid-range Morel's I replaced them with and have less "impact" (the speaker is starting and stopping faster accelerating the air faster causing a physical acceleration in my ear drums when reproducing a kick drum) and less clarity (I can hear the pluck of a bass guitar string and hear when it stops vibrating more precisely because the speaker is stopping and starting more quickly and more linearly reproducing the actual note as it was played) when reproducing mid-bass and bass notes.