Speaker jumpers

No

jumpers without replacing the internal wiring will do nothing

jumpers and replacing the internal wiring will do little 

non 'wimpy' is only needed if you are moving a lot of current - even current hungry magneplanars need only banana connectors for adequate flow at the highest SPLs

if you have a need to tweek work on room treatments

Yes, the engineers who designed your expensive speakers don't know how to build jumpers.

The best jumpers are the Mega-Magics from Confirmation Bias Cable Co.

maybe you can explain what is wrong with steel

also, the notion that engineers are overruled by cost containment of the manufacturers for expensive speakers is just speculation

you can always do your own blind testing of course... or spend time & money on something that really matters (speakers, room, best source recordings)

Creation "scientists" can explain everything...

Just look at the idiocy above