Battery Change, a Diet Opportunity

[Topless]

If you really want to put her on a diet, lose that 50lb lead acid battery and go 5lb Lithium:
ShoraiUsa - Batteries

[RobbieKnobbie]

For the battery itself, I was planning to stick with a conventional battery but go down a size or two. I seldom, if ever, start the car in 'difficult' conditions (winter cold) so the diminished capacity shouldn't come into play.

Again, I'm not building a race car, I'm just laying out a weekend project. In a few years when the Lithium batteries are more mainstream, I may venture off in that direction.

[Topless]

It was just a thought. My 5lb Lithium has 550CCA which is reasonably close to stock and 36Ahrs which is about 1/2 the stock battery reserve capacity. It cost around $225 which was $100 more than a new 50lb Bosch. A good tradeoff for me since I never even use the radio.

You can fabricate an aluminum battery strap that will look good but not offer any noticeable weight savings. Just make sure it is solidly mounted and never moves around.

[Spinnaker]

I would be wary of making a battery clamp/tray out of aluminum. Before you go to all the trouble of fabricating anything, drop some battery acid on a piece of aluminum and see what happens. Be sure to wear safety glasses, do it outside, and don't stand too close.
Fiberglass will be OK corrosion wise, but might have to be pretty thick to take the abuse.
Check out the Die Hard for the Boxster. It is a lot smaller then the stock battery and will save on weight. It comes with a plastic clamp that adapts the smaller size battery case to the stock tray. I've had one for 2 years with no problems.