You don't need to do anything because Firefox does that by default. I just finished downloading every file to make an Abit AT7 go from Abit's website. It got all of them at once, and there were six files. There is even an extension that instructs your anti-virus program to scan them immediately after they are downloaded.
I find that not to be the case. I am limited to two downloads at the same time from the same website. Where as with IE, I can download up to ten at the same time.
Probably so. Maybe these quirks from overwriting installs are history now that we have a final release. You have to remember that we've been using beta programs for months.