User blog comment:The5lacker/Varus is not a normal AD carry/@comment-4442345-20130614054641

AP does not scale with Crit. Before I would build Malady on ADC Varus, because everything about it scaled with Varus EXCEPT for some of the AP being wasted with crit chance, and the Hurricane would spread the Magic Resist reduction to their entire team as well (meaning more overall damage for everyone but say, a Talon).

The new Wit's End looks like it would be a great item for him though, and would still spread the magic resist reduction as well as gaining extra MR, which doesn't hurt on an ADC. I wouldn't recommend Nashor's and Deathcap though, because the AP doesn't scale with crit... Unless, you are playing purely AP, which I dislike and "die a little on the inside" when I see it.