[bluemax_1]

Haven't tried the Brembo's but I have the Stoptech 355mm kit, and yes, can recommend them wholeheartedly. Fantastic kit. Used them at Gingerman and they worked well, but didn't get to use the brake temp paint on track to see exactly how hot the rotors were getting. I'll post up when I do.

I went with the Stoptech kit because they custom develop, test and optimize the kit for brake balance/bias with the stock rears, so you can keep your stock rears (which only take up about 30% of the braking load at most) and have optimal balance. With the other 'generic' Big Brake Kits, they're simply giving you brakes made for another car with adapters so they'll bolt on to your car. Stoptech actually tests braking performance and sizes the pistons in their calipers accordingly.

To get proper front-rear brake bias with any other kit, you need to install a brake porportioning valve AND have sufficient experience, knowledge to tune it.

Obviously, even with the Stoptech kit, it's possible to improve brake bias with a proportioning valve (if you know what you're doing), by tuning the bias based on your tires and suspension setup (different grip, different suspension stiffness changes weight transfer and thus how much braking torque can be optimally applied to each axle). If you don't know what you're doing though, you can royally mess things up with a brake proportioning valve.

If you don't install/tune a brake proportioning valve, then most BBK's tend to generate more brake torque in front, decreasing your overall braking performance. Remember your absolute best braking is governed by the grip limits of your tires. Your tire's grip is dependent (in part) on the pressure on them from the weight on that axle. The best braking is achieved when you generate the maximum brake torque possible at each axle (optimally corner, but let's generalize with front and rear axles since we aren't talking about adjusting brake bias between left and right wheels) before wheel lockup occurs. This is called threshold braking and also requires experience and sensitivity to your car.

If you're generating more brake torque in front proportionately, your front tires will lockup sooner than the rears, and in order to brake without locking up the tires, you're underusing the rear tires' grip potential. This is what 'most' BBK's do, and it's relatively safe (safer than rear bias) since it induces understeer at the limit, but allows you to retain control of the car if you're not braking in a straight line. Obviously though, if you're underusing the grip potential of one pair( rear) of tires, your also not going to be slowing/stopping in the shortest distance possible.

If you screw up with a brake proportioning valve (or install bigger brakes in the rear) and develop a rear bias, your rears will lock up first and your car will either get seriously squirrelly when you hit the brakes, or you'll just completely lose control altogether (same reason why you never put snow tires only on the front axle). when your rears lockup first, the rear end will want to swing around on you whenever you hit the brakes.

Since Stoptech's done the work of testing and tuning the kit to optimize brake bias (by switching between different sized caliper pistons), you don't need to install a brake proportioning valve when using them with the stock rear brakes, but you can add that later if you have enough know-how or know someone who can help tune the bias for you when your setup is finalized (like I said, different tires, with different grip, stiffer suspension, weight reduction that affects weight distribution in the car all affect fine tuning of brake bias)

But hey, listen to lethal VR4. I'm just presenting the empirics and theoretical reasons for me choosing the Stoptech kit over anything else, he's actually got both kits and has had a chance to feel them in operation.


Max