I found this selection from Wright (see the whole lecture) to be helpful in clarifying his view on imputation:
The covenant plan of God has what may loosely be called a ‘participationist’ aspect, and this, too, is part of the glorification of God, as I have already shown from Romans 15. Abraham’s true family, the single ‘seed’ which God promised him, is summed up in the Messiah, whose role precisely as Messiah is not least to draw together the identity of the whole of God’s people so that what is true of him is true of them and vice versa. Here we arrive at one of the great truths of the gospel, which is that the accomplishment of Jesus Christ is reckoned to all those who are ‘in him’. This is the truth which has been expressed within the Reformed tradition in terms of ‘imputed righteousness’, often stated in terms of Jesus Christ having fulfilled the moral law and thus having accumulated a ‘righteous’ status which can be shared with all his people. [Read more…] about Wright on Imputation

