@bobpenn: First welcome to the forum, and thank you for your post.
According to Sony: Firmware Upgrade 2.0e
1.) Allows your Dual RW drive to record at 4X on 4X compatible DVD+R media.
2.) Improves reading and writing performance and reliability.
3.) Reduces vibration noise for the discs with unbalance or eccentricity.
Above is the official statement from Sony's website. I know that:
1.) Has been in effect since 1.0f version of the firmware.
2.) Is a general statement which every firmware upgrade promises.
3.) Speaks for itself, provided you had a vibration problem.
I guess we will just have to wait and see whether or not any features we now have disappear or not. It does put the X series drives, the ones that write 4X DVD+R out of the box, and the original drives under the same firmware.