You swapped onto a car not designed for the mod in the first place. And regarding passengers, I think the majority don't care about them as who really drives around with a passenger in this game once they've done those missions or test driven the car. Seriously if your lonely in the game phone up a mate or something.
If you want it done your way do it yourself. You know the tools needed and the models used so jump right in and do it better yourself. Seriously 99% of people are happy just to have another good quality car in the game to drive and admire but you seem to want it up to the specs of the guys at rabcat who get paid to do this as their job. Honestly lighten up and enjoy what is given out. Feedback is wanted and appreciated but if you list every single little issue that has no detrimental effect to the car and it's enjoyment itself then why the hell mention it?!
Go and complain to Eden and Atari that the high-level rear light on the Enzo is orange or that the Maserati Grandsport front right (I think) wheel rotates opposite what it should. You seem to want to go on and degrade the work these guys do even if it is a conversion it still requires a fair bit of work to get looking good in this game.
Conversions are like RUF cars, they take the core component and then alter it heavily to make it their own with lots of work inbetween to do so. Don't like it, don't download it.
Simples!
And are you seriously comparing the mods these guys do to the industry standard work people on that site you mentioned are aiming for?