Rel S812 fuse, AC cable, footers

I have a pair of Rel S812 subs that was set up by David Schultz last week and he dialed them in to perfection. One of the biggest increase in SQ I’ve ever done. 2 more pairs to go with 3 on each side. David, who was a head man at Rel and now works for T+A, said running the triple will sound amazing.

Rel now says that footers are not needed the way they designed the bottom rail on the S812. Has folks here, who own the S812, tried stands/ footers under their subs with positive results?

Has a fuse upgrade from the stock fuse caused an upgrade in the performance of the subs ?

Does a higher grade AC cable change from stock make a huge upgrade?

How many hours does a new pair of S812 take to reach break in?