Are you going to offer a choice of finishes and/or woods? Here in the mid-Atlantic, we tend to favor materials like mahogany and teak which are resistant to wood rot and salt water. Plus, some of us have boats and we like the idea that the trim on the GT40 would harmonize visually with the boat. Of course, if your GT40 were green, you could use pressure treated lumber. No spoiler rot, in addition to the aerodynamic effects.