[U]nderneath all this, then, is Christology. Here again the truth to which, at its best, the doctrine of "imputed righteousness" can function as a kind of signpost. God has "put forth" Jesus so that, through his faithful death, all those who belong to him can be regarded as having died. God raised him up so that, through his vindication, all those who belong to him can be regarded as being themselves vindicated. Since that is more or less exactly what Paul says in Romans 4:25, and spells out at length in Romans 6, the point ought to be fairly clear. "The faithfulness of the Messiah" is a shorthand way of saying that in Jesus, as Israel's representative (and hence the new, personal, middle term in the single-plan-through-Israel-for-the-world), God has accomplished what he always said he would. The faithfulness of the Messiah" is, actually, a way of stressing---as one might have thought any good Reformed theologian would welcome!---the sovereignty of God and the unshakeable, rock-bottom reality, with the events of justification and salvation, not of the faith of those being justified, but of representative and therefore substitutionary death of Israel's Messiah, Jesus. . . . [N. T. Wright, Justification: God's Plan & Paul's Vision, 206-07]
Obviously Wright follows the subjective genetive camp (e.g. the 'faithfulness or faith of Christ'); which ought to challenge traditional understandings that don't truly think from an 'in Christ' theology. A Pauline theology that sees Christ as the embodiment of all the riches of God for us (cf. Eph. 1; II Cor. 8:9; etc.). Faith isn't something of our own making; it's not some created thingy that God imparts to a certain elect group of people; faith is what Christ, in his humanity for us, operated with as the living bond of trust he shares with the Father, by the Holy Spirit on our behalf, in and through his mediatorial and priestly role for all those who will inherit eternal life (in Christ). This is the significance of what I see Wright articulating.