Finally something for the original question:
Guerrilla air 13cu/ci 0.2l
3000psi. At 1000psi, output 500psi
Weight 1lb 450g
Pure energy 48cu/ci 0.78l
3000psi. At 1000psi, output 600psi
Weight 3.5lb 1600g
Guerrilla air 48cu/ci 0.8l (both from markings)
4500psi At 2000psi, output 500psi
Weight 2.2lb 1000g
Empire air 91cu/ci 1.5l
4500psi. At 2000psi, output 800psi
Weight 3.7lb 1700g
Details are:
Make & size (sizes based on cylinder markings in cubic inches or litres and converted, with the exception of the .48, this accounts for differences in rounding on specs)
Pressures (maximum fill, current pressure, regulator output)
Weight (very rough on old school non digital kitchen scales)
All figures are approximate
An equivalent weight comparison of 48ci steelie and fibre show the fibre at 2/3 of the steelie. So there is a weight saving
However many people go for a standard 68ci and still talk about them being lighter because they are fibre
False perception - in this comparison the fibre is slightly heavier - because it is bigger