Hello
This is a base


And this is my s... - Chop




HS
https://images89.fotosik.pl/498/168fb2edcdff971e.png

Pretty nice. I think it lacks bit in lighting. Some parts are slightly "dull" and dark and that loses bit of the details on it. Also I am not sure of the rear seats angle or lighting on it?

Rest looks cool and the bg has this nice moody approach on it.

I always have problem with seats or interior

Avoid making the interior. You can just hide it with tinting the windows or hawing reflection on windows so strong that you cant see the interior. Probably will make the picture better looking too. As of now the rear interior is the first thing i looked when i looked the high res picture to see whats going on in there

Maybe is good idea, but I wanted make more details

No. It's not a solution. It's better to add your job to "Works in Progress" - more advanced people will help there