I'm looking for a download manager program/script but I need it to be more advanced. I am willing to pay for it if it exists.

The idea is, I want my website content to be 100% protected from outside my server. Means it blocks all leechers and direct link to my files/images.

Also, I want to select groups and giving files group tags that make some files downloadable for specific groups(in other words, must register to download some files).

I also want to control the bandwidth of each member. Like 1gb per month or something like that.

Extra features are always welcome. Is there any software like this around? please help me find one :)

You can block hotlinking from with Cpanel but for a full download management system, check out hotscripts.com

Is there anything made by a reliable source? made by a community or a company?

I had this idea that there would be many programs available(like for eCommerce you can choose from many brands) but I guess I was wrong.