(3) Do you recommend stainless steel brake lines? What are the advantages and disadvantages?
The primary purpose of stainless steel braided brake lines is to improve the brake pedal feel, i.e. to make the brake pedal firmer. Stainless steel brake lines are typically constructed of a PTFE (teflon) core - through which the brake fluid travels, which is covered with a nylon or kevlar braided sheath, over which stainless steel fibers are braided on the exterior. Some stainless steel brake lines also have a silicone cover applied over the stainless steel braiding, to prevent dust and debris from working into the space between the PTFE core and the stainless steel braiding, which can wear down the PTFE core, and thus result in brake line failure.
For a street driven vehicle, we recommend NOT installing stainless steel brake lines, as they require more "maintenance" than OEM rubber brake lines. By maintenance, we mean regular inspection for leaks or wear. The stainless steel braiding provides protection against road debris which could otherwise cut or rupture an OEM rubber brake line, but unless you are willing to inspect your brake lines every 3 months or so, installing stainless steel brake lines would present more of a liability than any realistic performance benefit.
For a track driven vehicle which has its brake system inspected regularly, and where the driver wants the most consistent and firm brake pedal feel possible, then stainless steel brake lines can be installed with excellent results.