Thank you for the impressions!
Are you listening with FIIO's bass boost (4-5dB boost), 5dB EQ bass boost and one bass port open(3dB boost)?
You must be the king of bassheads!
I don't think Pro 82 is a good choice for such extreme bassheads though - elevating the bass so much hurts the rest of the frequencies too much, even treble.
Opening ports doesn't just boost bass compared to the rest of FR - it also makes the other frequencies less controlled - that's why the treble may now appear "hot".
I am surprised that you still like Pro 82.
Can you do me a favor?
Put back the original pads, close the bass ports, don't EQ anything - just leave the FIIO's bass boost on.
Listen like this for a couple of days - do not adjust anything!
Then implement your changes again - you
might recognize enough deficiencies in the sound now to not like the modifications anymore.
With the default pads and closed bass ports, I hear/feel 15-20Hz with no problem at all - maybe you need the extra boost because of the HM5 pads and open bass ports.
Anyway, it's super useful to have impressions of a proper basshead - I will add a link to your impressions in one of the reserved posts on top.