I really doubt it will have more space than a G31, maybe a negligible ammount.
It has more in pretty much every respect, head room, shoulder room, leg room, luggage capacity.
I you want a car that is more comfortable than 5er, but cant afford 7er, why not but e class?
Because an E-class doesn't offer the other things that the GT does.... so... why not just buy a 6GT?

