I'm very happy with the Seymour Duncan SH-4 in the bridge of my USA Custom (Basswood body).
I'm wondering if I'll get somewhat the similar sound in an Ibanez S-470 as the S models has Mahogany body's. The old V2 stock pickups are just dreadful in comparison.
IMO for what it's worth it will make as big a change as it did with your first change, The wood does make a difference but I believe that most of the tone characteristics are down to the pup's. Like with you first pup switch - big difference you didn't change any wood.
I think wood is more nuances in sound and pups are what make the big difference.
Also each guitar is different, I have 3 guitars: my Ibanez RG570 (basswood) is the darkest, my Schecter hellraiser (mahogany) is in the middle, and my Ibanez RGA121 (mahogany/maple cap) is the brightest.