It's all about usage. I've taken my car to a couple of all day track days, and the BBK definitely made a difference. No fade, and much more confident diving into the corners. While steel lines don't do a think for stopping distance improvement, they can help protect a really important piece of your car (the fluid that makes it stop) and improve pedal feel slightly with less flex, which can also add to confidence in your vehicle. For a daily driver? Only do it if you need to have the bling.