Christology in 2 Cor 3:16-18

Chris Tilling crosses exegetical sabers with his supervisor Max Turner in a fascinating discussion of 2 Cor 3:12-18, specifically discussing 2 Cor 3:16-18.

12 Since, then, we have such a hope, we act with great boldness, 13 not like Moses, who put a veil over his face to keep the people of Israel from gazing at the end of the glory that was being set aside. 14 But their minds were hardened. Indeed, to this very day, when they hear the reading of the old covenant, that same veil is still there, since only in Christ is it set aside. 15 Indeed, to this very day whenever Moses is read, a veil lies over their minds; 16 but when one turns to the Lord, the veil is removed. 17 Now the Lord is the Spirit, and where the Spirit of the Lord is, there is freedom. 18 And all of us, with unveiled faces, seeing the glory of the Lord as though reflected in a mirror, are being transformed into the same image from one degree of glory to another; for this comes from the Lord, the Spirit. [NRSV]

It's exegetical discussions like these that blogs are rather spectacular for. My ignorance persists as I try and understand the complexities of the issue and in a comment I've posed the following to Chris:

So how do you understand "The Lord is the Spirit"? Vs 18's "LORD" can refer to Jesus if Paul is arguing along the same lines as Rom 8:29 with regards to image. The question in my mind becomes, why switch from Christ in v14, to Spirit in v17, back to Christ in 18? This does appear to be a rather complex passage...

Matters are complicated for me by the fact that my commentaries on 2 Corinthians are all in New Zealand! (Martin & Barnett, and Witherington and Keener hardly deal with the matter in any depth and Harris is a tad expensive at the moment!) Keener does appear to suggest that image would naturally lead one to the image of Christ but does not engage in much discussion. Witherington notes the discussion, but argues that LORD refers to the Spirit (Conflict and Community in Corinth, pg. 382). Actually, Witherington's position seems likely, as likely as any other position! But now it appears that Gordon Fee has changed his mind in support of a Christological referent. This leaves us hungry for more: How will Chris [& Fee] argue that this has a Christological referent?

This is delicious side-track...

UPDATE

Looking through Plummer's old ICC Commentary on 2 Cor 3:16 and he is quite adamant that Lord refers to Christ (pg. 102). So Chris stands in good company. I wonder what the updated ICC, written by Thrall, does with this?