Whether you know it or not there is a certain amount of non-specific feedback your car treats you to which when present goes unnoticed but when absent can often make a car unbearable to drive if no undrivable. In many cases you will hear someone describe it as "numb" or "imprecise." What they are really talking about is a lack of feedback. Unfortunately in many cases cars today are made to pamper our lilly white behinds (please don't email me to tell me your butt isn’t lilly or white … it was meant to make a point ok :) rather than provided us with true feedback. Oh dear no we don’t want the realities of the world intruding on our blissful travel along the pavement of life. Ok that is the end of my rant.
So what is the point of all this you ask. Simple: without feedback, that untouchable of untouchables, from your braking system you are left with no tactile sensation as to what your brakes are doing. And the biggest killer of feedback in a modern braking system are the stock rubber lines. Remember what the job is of your brake fluid from the last section: to transmit the force of your foot on the pedal to the force of the pad on the rotor. In middle of that you have your brake lines. Most of that line is hard steel, but to account for suspension travel some of it has to be flexible. Standard OEM flexible line is a fiber reinforced rubber hose and for a bit of time this is usually enough. But over time these lines become soft and begin to expand under the tremendous pressure stresses the brake fluid subjects it to. The result is when you press the brake pedal some of that force and pedal travel goes not into moving the pads but simply expanding the rubber brake lines. This is not only a waste of good effort on your foots part but also reduces your feedback and thus your overall ability to control your brakes and without control you are just a 3400 missile looking for a cliff to fly off of.
To prevent / solve this problem you could either replace your lines with OEM rubber at a cost much higher than your next choice: stainless steel (SS) braided brake lines. Contrary to popular belief the SS braiding is NOT what prevents the lines for expanding; it is there only to protect the line from damage. "Stainless-steel" lines are made of Teflon tubing, not rubber.
As I started doing some research for this section, I found perhaps the best written articles on the topic. In fact this web site itself has a TON of excellent information which appears to me to be excellently researched and in as many cases as possible backed up with real world data above and beyond anecdotal evidence; and any anecdotal evidence used is clearly marked. So expect to see a lot of links to this web page. With no further ado I present you with the Aftermarket Brake Line web page by Andrew Warren.
Now that you have read that what are your choices. Obviously if you submit 100% to Andrew’s assertions you should stick strictly with any kit or DIY version of SS lines that use Earls or Aeroquip fittings. I’m not quite so hard-line as him as I know several road race and rally cars/drivers who use crimp type fitting on their cars. Trust me these guys have no desire to fly off a cliff because of their brakes … no they fly off cliffs for other reasons. So with that in mind I feel I can recommend using lines supplied by Road Race Engineering, Diamond Star Specialties, and pretty much most of the DSM vendors who do something more than straight line racing. That isn’t to say the drag shops don’t have good brake lines but realize that isn’t an area they worry about as much. I also know that most of them will make brake lines with the better fittings if you ask and from what I remember per an email from RRE the cost might not even be more; they just won’t be DOT certified.
Also realize that if you are going to be upgrading your brake calipers you will almost definitely be getting new brake lines with them because of the different fittings; and chances are those lines will be SS. But they will only be for the ones you replace and you should ask for rear lines as well.
A hint which I will also mention in my FAQ about the line swap I did: you HAVE to use good line wrenches and even those might not be enough. A good pair of vice grips might be required to remove the lines. Just be careful not to damage the hard line.