Waiting period for a residence permit

I think you have to send all docs by email. Check the website for the email address.
They are generally heavily loaded and hence slow. It took  Typically 2-3 months in my case.

And you can pay for express to shorten the time. It will only cost some €80 or more. But as a rule the shortest time you can get your residence permit after paying for express is about 7-8 weeks

thank you, i didn't know about that, it's very helpful

If you order for the express before 3pm ( that is on the day of your appointment), you get it the following day. In Antwerp the express is €123.
Best wishes

If I am not mistaken, express service is offered only after your application has been approved. It means it only shortens the delivery time of your residence card, doesn't it?

Exactly. If your application is not approved, you won't be given appointment for residence card.