Still keeping my eye out for a smaller (packageable) fuel tank, but in the mean time I've found another place to pull a few more ounces off the car. I have the left rear suspension apart to find where the noise/slop is coming from. While pulling things apart I noticed I can probably replace the rear caliper steel brackets with aluminum substitutes. The braking force paths are pretty straight and short, and the 6061 material is probably comparable to the aluminum mounting tabs on the calipers. As I've said before, not a large weight reduction, as I'm scraping for ounces these days.