Ok, first thing first:
To export your favorits I have done this like 2 times cause I have re-formated my pc that many times, just try to do it once before you actually do it, here we go.
To Export Bookmarks:
1. Go to Boommarks
2. Press Manage Bookmarks
3. Go to File at the top of the new window that opens
4. Press Export in the file option.
5. Give a name to your Bookmark Export file
6. Save where ever you desire it
NOTE: For best results save the file to your email which you can do when you need it upload it to a computer you desire, hehe easy as a cake, the upload is almost the same procedure I will list it.
To Upload:
1. Do step 1-3 same as above
2. Go to Import Bookmarks
3. It will ask you if you want to import from IE or File in your case (file)
4. locate file and open
5. GO CRAZY WITH YOUR BOOKMARKS!!!
Question 2:
Yes you can use Download Manager's with Fire Fox, infact you can make it your Default download so it will dowload it right away to a location you have selected, but to do this you need to go to the Download Manager and click "Use with Fire Fox" and if you want to make it default it will ask you or you can select it either way.
Question 3:
I dont like the plain look sometimes of Firefox so I change the theme of it how it looks like, I got a link you can go to and check it out it's a Official FF site link:
https://addons.mozilla.org/themes/?application={ec8030f7-c20a-464f-9b0e-13a3a9e97384}
Oh by the way "undyingforce5" please tell me what version of Firefox you have got cause I have a little tweak program for it that helps you make it faster, stops pop-up's, and other tweaks for it. Hope you like this guide and hope all you you guy's use it.