Here's a few pics for you. I had a custom alum cell made to fit where my plastic one was. it's about 15 gallons.

Old brackets for the plastic 12 gallon cell.

I had some brackets welded to the alum cell so I could use the same tabs the straps used.

I don't have any good pics from the bottom. It's covered with a belly pan in the car. Here's a completed pic.