I Know this has been covered before, but my manual quotes 7daNM and forum members seem to think its 280NM (28daNM)

Hub nut was quite easy to undo. Car is low mileage (30K 2005) so assume original and therefor done by factory.

However bearing was noisy and new hub still noisy. Also hub nuts are usually very tight. So I really don't know what is correct.

I guess either no one knows or cares.

Or maybe the 70 NM in the manual is very wrong and I should know better.

Its just that I need to get home on Thursday, so need to know if my wheel is going to fall off.

I guess no one wants to carry the can for your wheel falling off!

Wish I could help, but I don't know what the correct answer is, and experience has taught me not to guess.

So I went to Halfords last night and bought a 32mm socket and breaker bar.
Tightened the nut in the car park as much as I could.
Still getting a hum, but will torque it up to 280 NM when I get home and see.

Somewhere at Fiat, there is a chassis engineer who knows exactly what it should be. Unfortunately Fiat didn't bother making this information available.

Contacted the bearing supplier SNR.

They were very helpful and answered my question quickly. The figure they gave me was 280NM.

So there you go. Ignore the Barchetta manual and listen to the forum.