In case you haven't noticed, The Longer Commentary of R. David Kimhi on the First Book of the Psalms is hidden away in the Classic Commentaries and Studies on the Psalms Upgrade (30 vols.).
I haven't had time to read it myself yet, but this looks interesting: David Kimchi's response to Christianity in his Psalm commentary.
(Btw, it would be nice to have Jewish commentaries bundled together, instead of hidden away one by one in these huge Classic Commentaries bundles.)