David, I also had a 3.0 litre Roadster. So I know them and I can compare. Regarding the 4/4 I only know my 2014 car. The cabins of the 2010 Roadster and the 2014 4/4 are definitely of the same size.
But...there is one issue which could lead to a subjectively very different experience!
It is the width of the gearbox tunnel in the leg room.
I.e. the 2014 4/4 is „ok“ but the 2010 Roadster has in comparison such a slim tunnel that it was at once appreciable in a very positive way. You could very easily think that the cabin must be wider but it is an illusion. It is not an illusion that your legs have noticable more space in the Roadster.
I don‘t know if a 2010 4/4 with a Ford gear box has another tunnel size than a 2014 4/4 with a Mazda gear box.
I.e. the first 3,7 Roadster were so problematic in this aspect because the gearbox tunnel was extremely huge and took a lot of the leg room away.
