That happens when I add a car too, When I add a top speed, the Mph is ALWAYS either 1 or 2Mph slower then what I listed, So I usually go up 1 or 2Mph when adding a car. Its actually ALWAYS been like that as far as I can remember, Or it could just be my system.
I think that the mph-kph converter on this site is wrong. The actual top speed of this car is 204.4 mph if in kph it is 329. There are many more examples of this on other cars on this site aswell
Whilst it is extremely heavy, I spent the day in one yesterday and was pleasantly surprised that it doesn't handle like a boat. Especially in sport dynamic mode. Its like having your living room in a rocket ship. it was getting a hilarious fuel consumption figure of 40L/100km in the city though.
This Bentley is too heavy to be a high performance car, especially after I've read a reported about Continental GT3 concept based on this Speed model, where was claimed that the curb weight is only 1350 kg! So if Bentley made a Continental Speed without all that options, which sometimes are useless, and used carbon fiber and light metals, it could have a curb weight approx 1750 kg or even a bit less! Then it would become a GT supercar by Bentley. I've read also that GT3 is able to accelerate to 100 kph in 3.2 s and the handle is much better. And imagine that road legal - it would become comparable maybe even to a Datsun GT-R!