I just put Goodridge steel lines on last weekend. I got the ones with a "carbon lookalike" finish to keep the cops at bay (not really legal in Aust), anyway they are a 200% improvement on the stock ones. I now have fingertip control and can go even later into corners...Although I'm a bit worried about the disks now as I have race pads in and can hear them giving the disks a good polishing now. Might have to opt for a softer pad and change pads regularly rather than disks!!
BTW don't know much about Kevlar lines, sorry.
Who needs more cubes?