I went with stainless tubing and fittings from Inline Tube, and while I haven't filled and tested the system yet to check for leaks, I didn't have any trouble at all bending, flaring, and plumbing in the system. A quality flairing tool is a must. My regular small rigid tubing cutters didn't have any problem cutting the tubing. Used a tubing bender for all the bends, imo you should always use a bender, and if you know how to use it should have zero issues creating an bend necessary to form with the chassis.
I think if you take the time with SS it really isn't all that hard. NiCop is cheaper though, easier to form, and will last just as long.
