I am not sure to understand...

You mean suggesting cars to add in the comments on imcdb rather than here on the forum ?
It is much easier for use to send new cars through the forum rather than through the comments.
One special case: extra picture for a car, these can be posted directly in the comments, like what admins would do.
Same for extra vehicles identical to a vehicle already listed.
I am not sure that my reply is very clear either