The overall sound is not bad, but appears to be heavily eq’ed. I prefer a soft dome tweeter and from the sound of the stock setup, that appears to be what is being used.
With that being said, the way manufacturers can get decent sound out of stock audio systems is to reduce the mass of the drivers themselves. Not the frame, but the cone, surround, voice coil, ect. All of the moving parts. It’s like taking a Geo Metro 1.0L 3 cylinder and putting it into a 500 pound vehicle. It is going to accelerate and perform the same as a 300 hp motor in a 3,000 pound vehicle, with the exception of top speed. Likewise, at lower volume levels the stock Niro stereo is going to sound good at lower volumes, but is really going to fall short when it comes to minute details, and with enough power aftermarket speakers can play louder too.
My last system was about sheer volume and it did quite well for how little I spent on it. At 80% volume on music that system hit 137.6 dB at 41 hz with a sealed box and a pair of 15” subs.
The Niro though will be a MUCH smaller setup with a single 10” sub in a custom sealed box that will go under the drivers seat. For now, I plan on keeping the stock speakers and radio. That may change down the road but for now I want to see if taking the replication demands of bass reproduction off of the stock system helps to improve overall volume and clarity. Only time will tell.