Jamie,

If money is no problem then go for it. If the wife will transition from "awwh, ..., okay then" to "Uh-huh ! ain't having none of that" then I would forego carbon in the split second that she needs to inhale before saying no.

Of course US$390 on a total of what 13.000 US$ is pretty small chance.

Stiffer is better and the additional costs seem to be reasonable. The final decision you have to make yourself I'm afraid, I'm not going to do that for you.

Wouter