Meabh
It's that the actual performance difference between the 4/4 and Plus 4 is greater than the 0.5 sec difference in 0-60 and 3mph in top speed stated by Morgan. You need to drive the cars to appreciate the difference rather than relying on figures that I am sure are made up rather than the result of testing.
Of course it's not just outright pace but the torque characteristics and power delivery of the two engines also make a noticeable difference in daily use as well.
Both cars are great fun, as is the Roadster, and it's very much personal choice which you prefer as all three trads are different to drive. What I was trying to get over was that you can't rely on the performance figures quoted by Morgan when comparing different models.