Don't forget about the Find button in the SongPicker. Assuming those file you downloaded are BIAB files, this is a quick way to find a song from within BIAB.

I unzipped all of the files into their associated folders within a 'parent' folder called BIAB Songs. The parent now contains folders such as _A, _B, _Latin, etc. To search these, I press the Find button in SongPicker. Make sure the 'Also search these locations' is checked and points to the correct location of the parent folder. Also check 'Include subfolders'. The search is extremely fast even with indexing turned off.

R