Sorry, just have to ask since I don't get it but have seen plenty of questions of the topic:
What is the rationale/need behind a DL manager? The last time I used one was when I was still on dialup. For more complex downloading needs, I'll usually use the usually-included, commandline-only
wget (sometimes combined with CLI scripting)
Anyway, d4x seems good, you may also want to try
MultiGet or some firefox-based extensions like
Flashgot