Here's the deal with the new Slash pickup. Virtually all the recordings you've heard Slash play on since 1986 were made with one guitar. Contrary to popular opinion, it's not a Max: it's a Derrig and it has stock Alnico II Pro pickups. The reason he uses that guitar, as opposed to any of his dozens of other Les Pauls, is because the Derrig just has a livelier, punchier, sound. When he plays live, he's less critical, but for recording, it's almost always the Derrig.
The new Slash pickup lets his other Les Pauls, what he calls his "live guitars," sound like the Derrig. That's it.