I found an article by Schreiner in JETS that explains this issue.
http://d3pi8hptl0qhh4.cloudfront.net/documents/tschreiner/Moo-JETS.pdf
"It seems to me, though, and I argue this case in more detail in my own forthcoming commentary, that Rom 2:28–29 reveals that Paul has in mind the good works that are done by the power of the Spirit. The new-covenant work of the Spirit produces good works in believers’ lives, and those who do such good works will receive eternal life. No contradiction exists with 3:20 because Paul there excludes good works as a basis for righteousness, but in Romans 2 he says that one will receive eternal life according to one’s good works. The distinction is an important one, for earning or meriting eternal life is excluded—but Paul also teaches that one must be changed in order to receive eternal life on the last day."
This article is also useful:
http://cruxsolablog.com/2013/09/16/the-role-of-works-at-final-judgment-schreiner-review-part-3/.
Given Jesus' various teachings and parables on judgement, which always demands that we show fruit, this seems like a reasonable explanation.
I should note that I accept at least part of the New Perspective, which Schreiner does not. (Dunn's commentary on Romans is my favorite.) But Wright seems to say something similar about judgement by works, so this is perhaps an area where the approaches need not differ. I suspect that this explanation fits better with the New Perspective though.
My own understanding of Jesus is that he teaches a fundamental orientation of our life, which he variously refers to as being a follower, a servant, and obedience. This a built on love for God and others, and shows itself in action. I don’t think he ever suggests that the two can be separated. But his parables of judgement are always based on people showing fruit. I believe this is the same thing that Schreiner is advocating. Since Jesus cannot be plausibly understood as teaching salvation by faith alone (which to me is different from justification by faith alone), this has the advantage of making Paul and Jesus consistent.
This isn’t “works righteousness” because it’s not works for their own sake, and they come out of faith. But I don’t think either Jesus or Paul ever supports the idea that faith can exist on its own, nor that God would value it if it did. Faith is the foundation of being a follower of Jesus, and for Jesus at least, it's the followers that are saved. If you look at Jesus' use of repentance, it always involves a change in the direction of one's life.