Metal Lines/fittings for airshocks?

You can go to your local big truck dealer(i.e. Kenworth, Freightliner) and get their black 1/8" air line. It's a lot more durable and holds up better than the white plastic that came with the original shocks. Another suggestion for you, would be to use very good 1/8" o-rings, the green ones if you can find them.

Bill S.