If u dont know what to do with the VegasS  file,  then stick it in this folder:

      C:\Program Files\Rockstar Games\GTA San Andreas\data\maps\vegas

I REALLY REALLY ADVISE YOU TO MAKE A BACKUP OF THE ORIGINAL IPL BECAUSE IF YOU DONT YOU CANT GET IT BACK WITHOUT UNINSTALING!!!!!!!!!

YOUR SAN ANDREAS MAY NOT LIKE THIS FILE SO PLEASE REMEMBER TO BACKUP THE ORIGINAL!!!!!!!!!!!!