By general consensus on this forum the Audio Magic Ultimate Premier is the best internal fuse for the P20, (and I assume, the P15).
Having got a P20 earlier this year I ensured I had the ultimate Premier fuse to install for initial switch on.
There’s (another) new fuse coming from SR, the Purple, released sometime this month and by all accounts of a prototype being tested by an Audiogon poster it ‘blows the Orange out of the water’ and makes his Orange fuse sound ‘broken’. Additionally he says the mid range is a big improvement over the Orange.
It would be interesting to see if any P165 or P20 owners on the forum will be testing the new internal Purple fuse against their existing Audio Magic fuse.