Downloading Sonnet Processor 3.1 for Mac from our website was free.
From the developer:
Sonnet Processor unified installer installs files necessary to support various Sonnet processor upgrades in the listed applicable computers. This software is not necessary for Encore/ZIF G3 nor Crescendo/7200 upgrades.
This installer also installs (or updates) the Startup Disk X control panel, and moves the original Startup Disk Control Panel to the Control Panels (Disabled) folder.
You may want to check out more software for Mac, such as Processing, which might be similar to Sonnet Processor.
Science Tools
Drivers