As a studio guy and engineer, I can tell you that what countless "audiophile car audio" guys offer is mostly a con. First of all, a car is not a great environment for discriminating listening - bad acoustics, road noise and such, so a lot of subtlety in the equipment, if it's even there, is wasted. Secondly, the state of the art in Class D amplifier chips is such that you can get a very good 100 watt 2.1 (stereo + subwoofer)
amp module for under $50, or a
standalone subwoofer amp for $20. Really. There's a whole range of these.
I have modules like this that, to my amazement, ended up running some big studio monitors, and sound (and test) great. If you have a DIY bone in your body, to wire some of these into an existing stereo setup like on the SR+, maybe add a couple of efficient midrange car speakers and mount a subwoofer in the back, can easily be done for under $200 complete. And if you do it right, it's not going to sound much different from what you can pay thousands for. That's assuming you're not after brain-damaging, window-cracking volume, but efficient speakers at 50 watts can outperform a 500+ watt inefficient rig. A little reading, and some Amazon Prime trial and error goes a long way.
Plus many of these boards have Bluetooth receivers on them. We have a pair of refrigerator-sized Altec monitors in the studio that run (loud!) off a
50/50 watt cigarette pack sized $20 DROK amp connected to our DAWs as "secondary monitors". But when people want to play mixes off their phone, we just flip the DROK to Bluetooth mode, and it's done. The point is, don't be stoopid, technology does get better, do some research, roll up your sleeves and don't waste money on alleged brand and image.