Plastic tanks are not universal in automotive and motorcycle use but they are common. Stronger penetration resistance, lighter, rust free for life.
Interesting. I found a site that says: "an average plastic tank weighs two-thirds less than an average steel tank." It also says that plastic gas tanks can be molded into any shape, are less expensive to produce, and corrosion free. See: Light-Weight Fuel Tanks | European Plastic Automotive Fuel Systems
One thing I do not buy is: "When a plastic fuel tank is exposed to fire, it is more likely to melt or decompose and allow the contents to flow out and add fuel to the fire. That reduces the risk of explosion
and enhances the safety of the car."
A steel gas tank is not likely to explode because it is vented and is not a sealed can.
See: "Cars Just Don't Explode
" : Cars just dont explode | Automotive Thinker - Discussing the finer points of automobiles
"A thing of beauty is a joy forever; its loveliness increases; it will never pass into nothingness" – John Keats.
Where Mustangs Began: 1963 Ford Falcon Futura Hardtop with a 164 hp Challenger 260 V-8 and a Ford-O-Matic two-speed automatic transmission. "The Wonder Falcon".
2016 Ford Mustang GT Fastback with a 435 hp Coyote 5.0 L V-8 and a 6R80E six-speed automatic transmission. "Race Red".