http://www.randbmotorsport.co.uk/sho...p?ProductID=40

There is no point what-so-ever going for the bigger 330mm discs with the standard calliper, as this kit uses the exact same bell as the 300mm kit, and the disc is just 30mm wider, which means that 30mm of the inner part of the disc is untouched by the pads (which looks shit ) .

There is no need to run a bias valve on 2wd cars with this set-up, and in fact, I would not recommend putting too much braking at the rear on a 2wd car, as this can easily destablise the car at very high speeds if all four wheels lock up together . I would personally prefer the rears to NOT lock up at the same time.

On a 4x4, you can put LOTS more braking to the rear and this won't happen, due to the wheels being linked by the 4wd system. However, if you have uprated callipers at the rear, I personally think it is a MUST to have a bias valve to ensure the braking can be adjusted to suit the car.