Dot 3, 4 or 5.1. Most brands are good, cuz they meet all the specs.
I heard to avoid Dot 5 cuz of that watever liquid they use......
Depends on how hard you drive and how hard you brake. I would assume the the higher Dot numbers would have a higher boiling point, so if you are not braking real hard, then 5.1 would probably be overkill, and you also have to flush the fluid more often then DOT 3. I personally will go with Dot 4.
As for the SS brake lines, they are not proven to improve stopping distance, but provide a better pedal feel as the metal does not expand as the rubber ones does. If I am not wrong, you also have to change the SS lines every few years.