Right... the new version is T.P. and super glue but same idea.

I believe you are right.  I also have a Pathfinder and I've played it at every possible volume.  When I get to the top of its power range, it sounds really ugly.  I'm convinced that we love this preamp.  The chip amp is just there to make it louder.  The speaker believe it or not, is a really good match for this amp -- they must have tailored it to the amp.  I bet this preamp would really holler if it was teamed up with KMG's power amp.

I'm a fan.  I bought two, new, when they first came out.  Actually drove down to the factory to pick them up and to spend a couple of hours with designer Gary Sunda who explained the whole genesis of this amp. Many years later I sold one, the other was stolen.  After a few years I missed it and bought one used.  Then another.  Then a wrecked chassis.  Now I have 4 in various states of repair.  It's a very good design, sounds good, nearly bulletproof and sounds better the more you turn it up.  I got interesting results by using a 16 ohm Celestion instead of the stock 8 ohm unit.  It dropped the power output somewhat.  Since the amp sounds better the more you turn it up, I'm able to turn it up more often.
An interesting side note is that a lot of the weight of these amps is in the MDF cabinet.  If you put the chassis in a pine or plywood cabinet, it's amazing how nice and light they really are.

I already have installed a 16ohm Celestion that is a mule/hybrid thing (It was a G12T-75 reconed using parts intended for a 16 ohmGreenback).  It did help some.
This amp really does sound different when cranking; there is feedback off the speaker that is used to modify the impedance/damping of the power amp.  Personally, I can hear it, so I want to get that same effect with less earsplitting volume.

I lack basic familiarity with SS power amp topologies.  This unit uses a pair of 2n6254 power Q's, cascaded apparently, per rail.  It has an elaborate biasing scheme I don't understand very well, but it does not look like there is any quick n dirty way to operate the existing amp to produce less power.  Technically, is the only real way to reduce the rail voltage?  Can I artificially limit the available current by modding the power supply and introducing intentional current limiting there?

I always liked these amps.  Currently, (electricity joke) I have two of them.
They sound fine but too loud.  I have taken one simple step that helped but I want to take it further. The amp is set up for 8ohms (80W) or optionally 4ohms (100W)
I'm a longtime tube guy and only dabble in SS, but I'm getting more into it these days.
How can I reduce the maximum power capability of the power amps section?  I don't know what to focus on.
Can I limit the current, can I reduce the rail voltage?  Do I have to swap out the power transformer entirely?  I'd like to get it down to around 20-30 watts max.
Can anybody point me in the right direction?
Thanx