"S&M²" included several notable highlights, such as the first-ever orchestral renditions of songs from "Death Magnetic" and "Hardwired... to Self-Destruct". Additionally, the concert featured unique performances, including a solo showcase for bassist Robert Trujillo and guitarist Kirk Hammett, and a classical piece performed by the orchestra alone.

The "S&M²" concerts were held at San Francisco's Chase Center, marking one of the first major events at the venue. The shows featured a blend of classic Metallica hits, tracks from their later albums, and symphonic pieces, showcasing the band's and the orchestra's evolutionary journey since their first collaboration.

The release of "S&M²" was met with critical acclaim and commercial success, charting globally and once again demonstrating the potent synergy between Metallica and the San Francisco Symphony. The project was also released in various formats, including a box set, providing fans with an immersive listening and viewing experience.

Michael Kamen, the original conductor and arranger for "S&M", had passed away in 2003. For "S&M²", the arrangements were helmed by conductor Edwin Outwater, with contributions from Metallica's longtime collaborator Bruce Coughlin. The new arrangements sought to honor Kamen's legacy while exploring new musical territories.