I'd make sure that the lines wont fit before you go buying new ones. Not sure about the r34 but i know in s-bodies the connection is the same as the r33/z32 brakes. Now i'm not sure about the brembos, they might require a bit more grunt. I know that going from crappy n/a sr20de front brakes to z32 brakes i didn't need to upgrade the BMC at all either. I can imagine that when going to the big brembos there might be more to it.