How lite is Liteweight ?

I remember reading about these large capacity capcitors and thought WOW the weight savings and still have the ability to do the job. Then typical me my life got sidetracked and I forgot all about them.
I wonder what the cost is to buy one like that and compared to the normal 4 batteries?

Re: about Aluminium chassis rails , my 1975 KW has what I think are extruded rails, 90 degree corners top and bottom of rails, rounded edges on the flanges. Being a Kenworth, the aluminium rails stop around the gearbox and a front sub-chassis bolts to the Al rails.

Interestingl, a lot of high pressure gas cylinders were extuded, I visitied the test range near Bathurst some years ago where cylinders, tanks etc were tested to failure buy CID (BOC?) , unfortunately no photos.. Some videos may be on Youtube.
Paul