My + batery cable corroded and severed. on 1999 Subaru Impreza Outback

I had the car towed to another nearby mechanic and the original quote multiplied 5x. they said entire battery cable harness needs to be replaced, not just the + cable. Does this sound reasonable?

Asked by for the 1999 Subaru Impreza Outback
another mechanic?? what happened to the first one??

the cables are special and the parts are not cheap. the bid sounds high by about 150-200.

I haven't told the 1st mechanic to do the work yet. $500+ just sounds high to me. Will get a 2nd opinion I guess.
yep, stay away from the dealer. they are always to the moon in price.