You don't even need to SBF, just make a backup of what you have immediately after root. These should be your steps:
-Root using z4Root v 1.3
-Reboot
-Run Droid X Recovery Bootstrap
-Will automatically reboot into recovery
-Create backup
-Install rom or whatever you want!
-THATS IT!
Now, when you want to get back to stock:
-Boot into recovery using Droid X Recovery Bootstrap
-Select zip from SD Card
-Select your backup
-Install that
-Reboot
-Unroot using z4root (one click!)
-Reboot
-Wipe data, restore to factory!
Just use Z4Root. You will need Z4Root (off the internet because it isn't in the market) and Droid X Bootstrap (from the market). Run z4root, and you press a button that says to "ROOT ME!". It roots you and reboots. That's it. Then do the backup by rebooting in to recovery like I said in the last post.
If you ever want to get to stock, restore your backup that is stock but rooted, and then run z4root and you will either be able to "Re-root" or "Unroot". Just click unroot, it unroots you and then delete z4root and recoverybootstrap. No signs of a root, but you can data reset if you want to make sure.
z4root takes one click to root and unroot, it take 30 seconds each way. I can root and unroot 500000000 times if I wanted to. All taking just one click.
Well I'm running ApeX 1.3.1 which is awesome because you can use certain Blur aspects if you don't want aosp entirely. It functions great. The built in theme is gingerbread so you get certain gingerbread features such as the keyboard, black menus and status bar, with the green icons.
Directions:
**Read this list entirely through twice before you do anything.
**I also HIGHLY suggest reading all of the instructions in the original post of ApeX if that is the ROM that you choose to go with.
---Download the ROM that you want to install and make sure that it is in a .zip folder, and that it is on the main directory of your SD card (it makes it easier to find if it is not in folders)
1.) Make sure you have Z4Root installed.
2.) Download and install Droid X Recovery Bootstrap from the market
3.) Reboot
4.) Run Z4Root, click "Root Me"
5.) Phone will reboot after rooting
6.) Run Droid X Recovery Bootstrap
7.) Click Bootstrap Recovery
8.) Click Ok when the pop up shows
9.) Click Reboot Recovery
10.) Phone will now boot into recovery
Now you are at the Recovery screen. Uses the volume rocker to navigate up and down, and the camera button to select. Also, the power/sleep button can be used to go back.
11.) Scroll down to "backup and restore"
12.) Click backup
13.) This will backup your stock ROM
---File will be stored in the /clockwork folder on your SD card, I recommend backing up this file to you computer also.
14.) back at the main screen, press "wipe data/factory reset"
15.) The press "wipe cache partition"
16.) Then go to "install zip from sd card"
17.) Then choose "Choose zip from sdcard"
18.) Select the ROM (the ziped folder) that you put on there)
19.) click yes
20.) it will install, should put you back at the main menu with the top option being to reboot system now, select this, and you're done!
Again, I suggest reading the 1st post in the rom that you think you are going to use, most developers also include instructions. Read everything twice (including this), and do it once, successfully. THERE YOU GO! HAVE FUN!
ADDED TO ABOVE: Make sure you are running the .340 OTA update for the new ApeX, he lists the requirements in the thread (1st post), which is why you should always read through.
I think he has a screen shot of what your system info should be.