Vanquish has a little more interior room than DB9.

 

I thought it would be the other way around. From the looks, DB9 looks bigger than Vanquish, but I guess based on your comments Vanquish has the bigger interior? I'm not a big person, under 5"9, so either will work for me, I'm more concerned about getting into the car and sitting position.

 

According to the Aston Martin guide says Vanquish has more interior room. Set one of the three seat memory settings to full height.