Since getting this guitar a week ago, I have tried several pickups. This guitars tone (mahogony) is different than most of my other guitars which are basswood. Something about it just didn't sound "right".
The guitar has a very strong upper mid tone, the higher strings ring out true, but the guitar is not warm and it sounds aggressive. This is good on the lower strings as the notes have a growl, but overall the lead guitar sound is thin.
So I tried a Dimarzio Evolution. Hotter than the stock pickups with much more mids. The playability of this pickup was great, but it's ceramic and doesn't have an extended top end. The notes sounded tight and nasally. Just missing bass and too aggressive.
Then I swapped a ceramic magnet into the Custom 5. This was now a "Custom". This was better than the C5, but it had a bit of that nasally sound of the Evolution and wasnt as hot. It just sounded like 80s party rock, not modern.
I put the Custom 5 back to stock and played with it again... something not right.
So I looked through my parts box .. and the only hot pickups I had... was an Ibanez INF2 stock pickup from some old RG 4xx. This is hot but it also happens to be alnico 5.
I must say, this pickup is absolutely the perfect match for this guitar. It has much more bass response, nice mids, and an extended top. The tightness is gone, it sings now, and its hot enough to shred. I think the INF2 is roughly equivalent to a Tone Zone; a moderately hot A5 with lots of bass. Perfect for this guitar!
I may try some of the actual Dimarzios in this vein; Tone Zone, D Sonic, Crunch Lab, etc, but this sounds pretty great to me now.
My feeling about these old Duncan pickups is that they assume the guitar is a great sounding instrument, like a really resonant Les Paul. IME, the Dimarzio pickups all tend to have much more bass, and my intuition is that they are mostly designed for import super strats that often aren't deeply resonant.
IMO, the Custom 5 is absolutely the wrong pickup for this guitar. Its not quite hot enough for a shredder's metal guitar, and it doesn't have much bass (compared to Dimarzio style pickups).