It supports up to 128-voice polyphony and is 16-part multi-timbral.

Sites like Musical Artifacts host legacy plugin collections that include the Super Quartet.

However, because it was a popular tool, it often appears in "abandonware" or community-driven archives:

Everything You Need to Know About Edirol Super Quartet VST The remains one of the most recognizable "legacy" VST instruments in the digital music production world. Originally developed by Roland/Edirol in the early 2000s, this plugin was a powerhouse for its time, offering a high-quality "quartet" of contemporary instruments: Piano, Guitar, Bass, and Drums .