Okay so my Droid x2, is currently running Android 2.3.4 and I'm wanting to root my device. I may, probably not, (correct my lingo) flash a modded firmware?
Yes, you may flash a custom ROM (modded firmware), but in order to do so, you have to install a custom recovery which can flash .zip files. For the X2, the recovery you use is Bootstrap Recovery. There are also certain steps to take to insure you have a successful flash without losing a lot of your data.
I plan on following
This guide and rooting my phone, now to me it looks simple to unroot, just clicking the unroot button, but whats all this about Freezing/Deleting apps? Do I have to do this?
Freezing apps is simply preventing some of the factory installed apps (apps you can't uninstall without root) from running at all. It's bloatware the carrier puts on in hopes you use their stuff. Pretty lame there. Some people simply delete them. But sometimes when you delete the wrong app you can screw up your phone, and often times there is no way to re-install it. So lots of folks just freeze them. They won't run, they don't show up in your apps drawers, but if the absence of the app screws up the phone, they can simply un-freeze it.
And no, you don't have to do it. It's a personal preference.
Also how do I make sure my contacts are back up in case I do decide to unroot?
Just go into settings, choose accounts, and choose your Google account. Then you can sync contacts or whatever else you wish with that Google account. You can re-sync with any ROM or phone you wish to, you'll never lose the info since it's kept on Google servers, but if you only unroot you won't lose them anyway.
Also what is Bootstrap, do I need that for recovery? Where do I get it if I need it?
Besides flashing custom ROMs, Bootstrap performs other actions. It can flash scripts, mods, themes, etc. It can create and restore nandroid backups (a complete backup of your entire phone), wipe data and caches, fix permissions, wipe battery stats, create sdcard partitions, and some other things that aren't coming to mind atm.
We keep the
Motorola Droid X2: All Things Root Guide (the sticky right above your post) up to date, and it has links for everything you're talking about.