J. Shaw’s commentary is now available on Amazon here (for 10.95 USD), and the latest pdf version is available as a free download here on his website. He has previously published Pharr-formatted commentaries on Bk 1 and Epistle to the Hebrews.
Pharr-Formatted Augustine’s Confessions Bk 8 available in paperback and pdf
Greek and Latin Texts with Facing Vocabulary and Commentary 