But if you use modified .sbf file or some of the Update.zip files, then it will restore your phone to default state with Root. (You will also have to make the automated call to Verizon to activate the phone again, not too bad, like a 2 minute process).
The only thing that would be changed with mine is the fact that Verizon pushed a software update (not Android update) for droid 2 phones that i got as an over the air update. But from what I read that doesn't affect the process.