ok.. let's hijack the thread a bit more 
please can you tell me more about what problems apear when using fastEntireScript and grep prefrences?
I never noticed anything, but now that you mention it i had some very very wierd bugs in the script i'm still working on and that uses tons and tons of greps.
also, if the findWhat is not nedded (true, didn't even look at it), you can then use findTextPreferences, and changeText() for a large speed boost.