I put EBC organic pads on my '81 R65, saw no improvement in dry braking, but a significant increase in wet braking .
There is a product Permatex Disc Brake Quiet, it's an aerosol can that has a light blue material, spray it on the back of the pad that contacts the piston, keep it off of the friction pad, let it dry for few hours then install the pads, it kind of acts like an adhesive that glues the pad to the piston, stops the squeal, but the pad comes right off, as long as the parts are cool .
Another trick, is to use a rattle can of automotive paint on the back of the pads, does the same thing as Permatex, but stays glued together when you try to remove the pads .
As far as brake lines, that's your choice, but your lines are probably 33 years old, wouldn't be a bad idea to replace them .
After you do some searching, you'll find that stainless lines are fairly close to OEM rubber lines in cost .