So we bought the Fiat 500C manual transmission for a 4-down tow.The dealer said the car had to be in neutral with the key in MAR (run), and they had a printout to prove it. Not happy! The basic and extended US manuals said nothing about key; just neutral. Fiat Support first said the same think N+MAR. I researched the Euro manual, and it said Neutral and no key. After a week of research inside Fiat, Support verified Neutral only and Key OFF (can be removed!). Good news!
And they were willing to document it for future reference in writing.
What an easy tow. We have put about 500 miles on it in the past week, and it's a breeze.
Just FYI in case anyone runs into the same conflicting info.