May I ask what kind of experience you have with sound quality installations in cars? I don't mean old school radio, eq, amps and speakers. I mean DSPs, custom speaker placement, time alignment, individual driver EQ, etc.
I agree that cars are virtually the worst environment for audio imaginable but I don't believe you give enough credit to how good they CAN sound.
I also kind of interpret the OP's post as a direct comparison between "audiophiles" and "wax fanatics". Those that claim they can hear the difference between 6ft RCA cable A and 6ft RCA cable B. Similarly, people believe there are drastic differences between the depth, gloss, warmth, etc between waxes. To me, in audio, speaker choice is the biggest factor in the overall characteristics of what we perceive(hear). I'm generalizing, I know, but just imagine all other things are equal. Speaker choice plays the biggest role.
As for the way a car looks, I believe the prep is the most important factor. There are minor differences in LSPs, sure... but how apparent are the differences on perfectly polished paint?
Well, of course... as I mentioned... one can spend stupid amounts of money in car audio. I've had experience with custom tuning individual crossovers for speaker sets. Also have had (still do) several AudioControl components, most similar to their current EQL, EQS, EQX type components. Of course in addition to the Morel drivers I mentioned earlier I've had Altec, JVC, JBL, SEAS, Vifa, Scanspeak and may other drivers.
High end auto installs can (and do) sound quite well. But given the constraints, there just are too many physics going against any installation that you simply don't have when installing into a proper room. Dollar for dollar you can take the same expenditure in a rectangle shaped room and have exponentially better sound.
The inherent problem that will always exist within the confines of an automobile/truck/van etc. is you just do not physically have the space to reproduce a given sound wave. For instance, low bass will never physically be able to be reproduced inside the confines of an automobile due to the wavelengths involved. (IE: 24Hz=28.25ft @ sea level @ 72°) And that is before it hits a wall and needs to reflect back, double that for a full sine wave inside the area. Move down to 20Hz and you need a full 56.5 feet! Then take synthesized/electronic bass from a lot of today's music where they'll mix it down to 14~16Hz and you're looking at a wavelength of 70~80 FEET!
Yet inside the vehicle you indeed have the impression that you are experiencing true, low, bass. How does that happen? Simple, you are pressurizing the internal area, and your entire body, eardrums and everything else is simply oscillating (more or less) in unison with the bass drivers. Open the hatch, all the doors, give the sound a place to go and WHAM the bass outside will truly reach "sub" levels. It's turning your body literally into a passive radiator.
Which also goes to why the cops travelling around outside say the bass is so loud to them when inside all you're doing is just having a good time.
I had a client one time that called me in to look at his room and help him get the bass from it that he really craved. The room was already well constructed, dual layer sheetrock with Isodamp between the layers, and the sheetrock mounted on hat channel screwed to staggered 4x6 studs. Not much sound was escaping from the room, which was a GREAT thing. Also the dimensions were pretty good as it was almost 3 times as long as wide.
The thing is he had is sofa located in the wrong place. When he called me he was a big fan of Jurassic Park (where the dinosaur stomps and the water vibrates) he wanted the ROOM TO SHAKE when the dinosaur STOMPED. So I pulled out my tape measure and started taking measurements. Front to back, side to side, speaker placement, sofa (prime listening placement)... the whole thing. Plugged that into a spreadsheet I had at the time and it gave me the more optimal measurements that we should be working with.
Then I played a few test tones while I went around the room with my spl meter taking measurements.
"Good news" I said, after spending half an hour doing all of the above. Then I asked him had he ever noticed when he was standing right behind his sofa (which was about in the middle of the room as it was a 32'+ long room) did he notice that the bass was MUCH better standing behind the sofa than when he was sitting on the sofa.
"Sure" he replied, "But I thought that was because I was just standing up and getting more bass off the ceiling".
The thing is, that wasn't true. The truth was where the sofa was sitting he was directly in a -8dB - 34Hz suck-out. I told him if he'd move the sofa back 3 feet that he would solve his bass problems. Because THERE was where the bass was! That I could save him THREE to FOUR thousand dollars, just move the sofa!

He laughed and said that he wanted more than that. :laughing:
He said he wanted THE ROOM TO SHAKE. So I replied that we could do what the car stereo guys do, pressurize the room.

We could make it so, that with so many bass drivers that you had no choice to not only hear the bass (even if it wasn't accurate) but you would indeed FEEL THE BASS no matter where you were inside the room.
At that point he ordered a pair of custom built passive subs, with 4 NHT 12" drivers in two cabinets (two sealed boxes per cabinet) that stood 7'3" tall and weighed in at around 375 pounds each. We took those drivers and wired them in both parallel and series so that each side represented a 4 Ohm load to the amp. Then we drove each of those subs with 2000 watt class D amplifiers (4000 into 4 ohms, just over 6000 peak into 2 Ohms). They were crossed over at the THX specification of 80Hz with a steep 18dB slope so as not to get into the mains. Then he had Ty build him some mains with dual Eminence 12's, twin 6½'s and a horn loaded 1" dome tweeter. Those darned things would beat the living snot outta' ya'.

Not accurate, neither did they have a deep and wide soundstage, but for movies (especially action movies) they were most impressive. Of course there were custom sides and rears to match that came with the package.
About a year later he called and wanted to get rid of all those speakers EXCEPT the subs. Just got tired of the insane levels of bass, and being literally beat to death by a wall of sound in that room that was devoid of the openness and depth that he'd decided he would rather have. That was when we went to an all RBH setup. One that was VERY expensive because they have passive subs both on the bottom and the top of their largest speakers. Those speakers were well into $37K by the end of the day. And while they had bass drivers on top and bottom, plus 4 mids and 3 tweets each, the accuracy, timbre, depth and openness of the soundstage was magical.
Moved the crossover on the monster passive subs down to 45Hz with only a 12dB slope (bringing in the mains @ 60Hz with an 18dB slope) yet that still pressurized the snot out of the room.... with more low end bass than you could imagine.
And yes.... when the dinosaur stomped.... the GLASS OF WATER DID SHAKE! :dblthumb2:
(
Along with the whole foundation of the home.)