I’ve done it on lower end models (not all). Not so much cores/CE level. But I would say if I had to change a core it would probably be 85/15. I’m much more a PAF vibe kind of guy. And if I wanted higher output I’d probably go Dragons, HFS/Bass, or metal if I’m staying in PRS land. I never bonded with the 85/15. But it’s all personal taste.
I don't want to even start going down that rabbit hole....... But I will say I ended up going back to PRS pups. BTW only owned Core and up. Have not owned an SE or S2 and a lot of players change pups in the SE guitars. I do have one Custom 24 with Lindy Frail pups that I adore. I bought them off Reverb as High-Outut model but specs were different. I called Lindy, without the original receipt they could not tell me exactly what they were other than they were custom wound. I've used other pups from Lindy Fralin and just love them.
Put dimarzio paf pros in my S2 standard 24. I've put paf pros in pretty well every guitar I've had over the last 15 years. I just like the voicing and feel and response of them. Hadn't had much experience with alnico 2 magnets, but the ones I had tried I simply wasnt crazy about.
Only once, in my SE 35th anniversary. The stock ones (confusingly just known as "TCI-S pickups") were too bright for my liking. I really like the 58/15-S's in my SE Hollowbodys, so I grabbed another set of those for about $100 and swapped them in. Very happy with it! Even was able to sell the TCI-S ones for the same price, so it didn't cost me anything
Of the prs guitars I currently own there are three that will not get pickup swaps.

1986 cu24, stamped T and B
2011 cu24 5909
1997 ce22 dragon 1s
These three are incredible as they are.

I put 5310s in a 97 hog ce22 and that combo sounds fantastic so it's done.

My 2000 McCarty and 97 ce24 have had many swaps.