Classical recommendations needed

I would appreciate your recommendations on recordings of:

G&S: Pirates of Penzance, Mikado, Pinafore
Brahms: String Sextets
Mozart: Marriage of Figaro


I do not have any of the CDs you mention, but since no-one else has answered, Gramophone recommends

Brahms: The Raphael Ensemble, Hyperion CDA66276

Mozart: conducted by Vittorio Gui, Sesto Bruscantini as Figaro, Classics for Pleasure CD-CFPD4724; or conducted by Sir John Eliot Gardiner, Bryn Terfel as Figaro, Archiv Produktion 439 871-2AH3; or conducted by Erich Kleiber, Cesare Siepi as Figaro, Decca Grand Opera Series 417 315-2DM3

I think the D’Oyly Carte Opera Company are regarded as setting the standard for Gilbert and Sullivan.