Sizing up a Torus for a system I found is very important as I found out.
A few years ago I was using a 15a balanced Torus with 3X7B-sst's+2X4bsst's+compoents.
I didn't notice anything different from my Shunyatas(nothing more,nothing less).
I like to keep amps+components separate,I picked up a 20a Torus(balanced).
As soon as I reconnected everything and fired her up,WTF

...
Everything opened up big time,no trying to hear if it was better,you hear it.
I believe the 15a couldn't deliver what the amps required(even in a small room).
Starting off with a Torus with less power storage,definately showed me that having the right size Torus makes a HUGE,HUGE difference.I can't wait to upgrade my amps(28s) to compare the(direct to wall,and into the Torus(s)to see what difference there is.
If it's minor,with the Torus,there still is PROTECTION(as I found out also),
Even having extra reserve power for the newer amps(squared)amps makes sense),
Of course I haven't heard the upgraded squared amps yet,but soon I'll be doing the caps and transformers on my 28s and then I'll know.