just as the question states could you use steel braided lines for the transmission cooler lines? as my earlier post stated i broke one of mine and i thought it would be cool to use steel braided lines for the transmission cooler while switching the gas lines and what not to steel braided also.

Yes, as long as you use oil-resistant hose. You'll have to be sure they don't/can't come in contact with the battery cables(near the starter) or the exhaust though.

I believe most guys run -6. Brutalform did it on his a few years ago. No problems.

i run -6 hi temp hydraulic hoses on mine.

I use -6 AQP.

Yeah, I used hose after I broke my cooler lines. No problems here.