I have the 2.5 my sister gave me. I completely cleaned it up and replaced some parts but have yet to run it.
I'm just not a nitro guy. If anything, I love 1/5 scale gas RCs but even those are getting to heavy for me to handle.
The blue one is the 2.5 and the silver is the 3.3.
I can't answer the clutch question.
There is however a few guys in here that can, just be patient, they will come around.
@STONER RC has done the nitro to electric conversion and he can answer your questions.
Problem is, he works his ass off so...