[ryerman]

I guess there is some configuration that will give the performance you want.
But I don't want to associate any file types with Winamp, so I won't experiment to find a solution.

However, you can drag and drop files onto the Playlist Editor.
Or onto a Shortcut, with /ADD appended to the target. ("C:\Program Files (x86)\Winamp\winamp.exe" /ADD)

Winamp has good command line functionality.
To investigate, type "winamp /?" (without quotes) in a command window opened at the folder containing winamp.exe.