I didn't find the diagrams, but found some specs for the Scorpion that do show an increase of about 6" in length over the diagram you posted. I think all the other dimensions are the same, so that says "big bumpers" to me.
I haven't made any decisions yet. Still trying to get informed about them (never had a Scorpion, or any Lancia), and consider the options. Frankly another project is the last thing I need, but that has never stopped me.