I run a 3/8" stainless line on my Duster. I just bought it from Inline Tube, it follows the factory routing and was pretty easy to install. I have 1.5"x3" subframe connectors and they don't really interfere much with the original routing.
With 5/16" tubing you can make bends pretty easy with just a cheap bender, but with a lot of the 3/8" lines (especially stainless) making accurate bends gets more difficult unless you spend money on a nice bender. Pick your poison I guess, I just bought the stainless 3/8" line.
