Re: Parson Street magnet swap?
I haven't tried those. But in general, as you move in order from A3 to A2 to A4 to A5, at the same amp settings, you will be adding slight amounts of output, compression, and treble. IME, there is a bigger e.q. jump in the treble department from A4 to A5 than there is between any of the others...though output moves pretty evenly upward from one grade to the next, in the order I listed. I have not tried A8, IIRC, but I have seen specs that state it is a very powerful alnico magnet.
IME, the main thing you are changing when moving from one to the other is how sensitive the pickup is to your picking/plucking hand. I hit hard, and I love my small combo amps, so I tend to lean toward lower output mags in my humbucker equipped guitars. I you play amps with lots of headroom, and don't pick/pluck very heavily, then you will probably prefer stronger magnets.