First of all DVD speeds are not the same as CDs.
A 4x DVD driver writes a full disc in about 15 mins while an 8x DVD driver writes the disc in 7-8 mins.
Your drive is like mine, it burns DVD+R with maximum speed 8x and DVD-R with 4x. There are many posts that explain the differences which are very few.
To erase a DVD-RW there is an option in your DVD burner program like \"Format DVD-RW\".
You can fit about 6 episodes of anime with good quality in a DVD, maybe even 8.
You\'ll need DVD Shrink to back-up DVDs, Nero6 to burn DVDs, TMPEGEnc Plus to convert AVI files to DVD MPEG2 and TMPGEnc DVD Author to author them. There are guides about every one of these programs in the site. I hardly suggest you use these apps and not the ones that came with your DVD burner.
Finally all DVDs hold 4,38GBs, there are not any that hold more.
Also you may want to read the DVD FAQ which answers 90% of the user\'s questions about DVDs:
http://dvddemystified.com/dvdfaq.html
