use the hard lines. Rubber is only good for temporary repairs. Braided would be considered permanent but also the most expensive option. Many folks change their AOD's over to T5, and a lot of times they'll throw the old trans cooler lines away. See if you can find one of those guys. They aren't terribly hard to make if you had to. Also, I was at the parts store yesterday and bought some 3/8 rubber fuel line for a lawn mower I'm working on and I do believe that rubber hose is about the same cost per foot as steel line. It's nuts! With this inflation, I personally can't afford to continue playing with cars. One or more is fixing to go on the market.