http://imcdb.org/movie_80881-The-Hollywood-Knights.html
Done
The black Porsche (15) is the Porsche 356 A Speedster already listed http://imcdb.org/vehicle_53525-Porsche-356-A-Speedster.html

1.2 stars
2.1 star
6.1 star
8.1 star
11.1 star
14.1 star
15.2 star

Roles=Stars of the vehicle showed the pic.
http://www.imcdb.org/stats.php

1.main characters hide in it
2.main characters park there car next to it and converse by it
6.is a different truck the main character walks by
8.no thats already listed its for the white rambler right next to it
11.main character drives by it
14.drives by main character
don't forget the black porsche is the third porsche in the movie thats not listed yet

Tell the roles in each case ONLY for:
1, 2, 6 (same truck number 1?), 8 (yellow), 11 and 14

But the one on the left of the Corvair is too far / not enough visible

i am not talking about the corvair i am talking about the thunderbird to the left of it!!! i know my corvairs!! because i own and owned corvairs!!!
and that black porsche is not listed because there are 2 black porsches in the movie and only one is listed now!!!

About 1, even if not very visible it seems to have a role since there are actors in it. In such case it is still worth listing. Do not worry too much for the ID, sometimes such common vehicles may be more easy to ID than what you'd think

1.- 195? Ford truck and what more? Where are extra details for its ID?
2.- usable
3.- Well, usable, but still it's a far background partially obstructed by the clear blue Mustang
4.- 1955 Chevi Belair. Only thing sure is that it's a 55. From this date on: can be a Wagon, can be a coupe, can be Two-Ten, could be anything.
5.- Completely obstructed
6.- usable
7.- Fuzzy and blurred
8.- If you refering to the white on the right: dark, far and little.
9.- Already listed and it's a 1964 Chevrolet Corvair Monza
10.- Dark and little. Usable in comments of the movie as a goof of the movie.
11.- usable
12.- Van far, dark and little
13.- 13.196? (red) ford. Already listed and it's a 1965 Buick Skylark
14.- usable
15.- Already listed Porsche 356 A Speedster
16.- Porsche: are you sure?. Porsche 914?? without any detail for its ID?
17.- In the dark of the night this could be anything

I don't want boring with you about "the background problem", but try to be more selective and look for new movies, not specially for others previously listed.

Images are better, it looks like you're getting the hang of it