personaly i'd go steel. my concerns with nylon is durability when you have a wee fire. you never expect to have fire, but you never know when your competition in the brand X car, in the next lane has an ooopsy & crashes into you & you're both on fire. will those nylon fuel lines not melt thru in the short time you need to get your butt outta the chair & escape? i don't know but do you feel lucky?