You are asking two different questions here. Are the existing transmission cooler lines damaged in some way? If not, then don't worry about changing them. As for the shifter, the shifter instructions discuss how to set up the mounting as well as running the cable. Pay close attention to how you run the cable so it does not come too close or touch the exhaust.
I recently put in a B&M floor shifter, and used the stock tranny lines. They were not damaged, so I didn't change anything. I did order a new set of tranny lines to replace the old ones because I was under the car anyway, but they didn't match up the right way. I'd only replace them if needed.
wouldnt a mesh line let all the fluid leak out?
Once again, you beat me to it. That was EXACTLY my first thought.
