A8 mags tend to warm up tone a little bit, highs getting rounder. I think it will sound muddy at low end.
not in my experience
I did that with a holy diver and the results were exactly the opposite
the high end sounded very dry, unlike the stock holy diver, and the low end sounded a lot tighter
sounds like you're describing going from ceramic to a8
the stock diver sounded amazing in the 3 les pauls I had it installed, but too muffled and muddy in a gibson sg, so I had this a8 bar laying around and tried to fix the "problem"
i the end, I had a articulate sounding sg, but it wasn't toneful at all
it was a great sounding guitar and a great sounding pickup (in stock form), but they simply weren't made for each other
it might sound good, but you will feel a big difference in volume and probably lose a big part of the smooth and spongy feel of the alnico 5 pig
I'm not gonna try to convince you not to do it, as I love experimenting and I rarely regret any of my good or bad experiences with gear as long as I don't lose lots of money
if you don't mind losing the warranty and already have the magnet bar, just do it and tell us what you found