Sounds obvious which you want. I bought a brand new Miata Sport in 2000 and loved it, but it just felt way to small to me when I tried to use it for a daily driver so I only ended up driving it on weekends. If a Honda s2k feels as small there is no question which I would choose. Are you good at working on cars, do you like to, is money not an issue for parts, then don't worry about 'total ownership'. Go drive both and buy the one you love, not the logical one...assuming this is a toy. I got several logical cars in my life and I kept the best care of them and loved them best I could, I still however traded them 2 years later, logic didn't make the 4 year mark.
Post pics of your Boxster once you get it