You can do what ever you want on your car, hell, I've seen some pretty odd things. I myself only use steel line if it is to be a hard line. Copper for the most part is not supposed to be used, I don't know why or care why, it just isn't. I not one of those guys that have to question everything in life and I am not going to be a test dummy because I think something will work just fine. I have seen plastic line run to a fuel pressure gauge inside the car once and that same guy argued that he has been running it like that for years and I was the *** for not passing his car in tech. So you guys that want to be self engineers, go right ahead, but don't sell it to other people when it's not the correct way just because it worked for you. Someday someone else may own one of these self engineered cars and may cause an injury or death. I will tell you if I purchase one of these self engineered cars and don't catch the problem until it harms me are my family there will be a death involved, it will be the guy that did it.
Why would you not use a steel line? to lazy or cheap to buy a bender or you can bend the copper by hand? M.I.C.K.E.Y M.O.U.S.E
Chuck