why have you restricted yourself to "book shelfs"? If you really intend to place them on bookshelfs, then you likely won't find a speaker that provides good bass and belongs on a bookshelf. If you intend to place them on stands, you really should consider Totem's other floor standers - including Arros, Sttafs, Hawks, and Forests. All can be found used for <$2000, all except the Forests can be bought NEW for <$2000. Finally all have excellent bass. Further, they occupy the same of less footprint than a stand mounted bookshelf speaker, AND, you needn't buy a stand - saving at minimum $150.
It's true the Mani-2s have excellent bass (actually excellent everything!), and they can be bought used for <$2000, but they are not a bookshelf speaker. They need a heavy stand. They also need a good deal of power to fully appreciate.