Had to post this somewhere, otherwise, I'd forget and didn't want to write it down.
Note 2:5, Paul's entire point is dissuading putting faith in the wisdom/power of men, but says it must be in the power of God. He means it must be in Christ, for Christ is "The Power of God" (cf. 1:24). This fits with his entire point/argument. So it could rightly be read, "so that your faith is not in the wisdom of men, but in The Power of God (i.e. Christ)".
Paul's whole point is to take boasting and confidence in men away (be them us or others). He starts with others (1:12-17), moves to self (1:26-31), and moves to others again (2:1-5). The flow/structure of the argument itself provides even more basis for seeing imputed righteousness since the entire point is to take boasting away from ourselves/others, but to put it in Christ.