Solder wire is good for piping, but only if you can find it big enough. I'm sure there is some big enough out there, but I don't have it and my piping tends to look a little small, like something you would use to pipe a daily driven turbo Civic, not a killer Nissan. People have good luck with aluminum tube, but I cannot bend it to save my life. Failing solder, I have used old sprue. I like the silver paint on it anyway, its more like the heat resistant coating thats on most piping like that.
I really like this no-front-bumper idea. It's going to look hardcore. Can't wait to see how it turns out!