Why do my brakes need uprating?
They may not. An overhaul and better quality pads/shoes may be all you require. The main reason for having more powerful brakes is to stop faster or with more confidence. If you are happy with your brakes then that is fine.

What is wrong with standard brakes in good condition?
Nothing for general town driving. The problem occurs when you need to stop quickly from higher speeds. The standard brakes are limited in this area and can easily overheat, which results in brake fade or at worst, temporary failure.

Why should I use vented discs?
Braking is all about slowing forward motion by friction. Applying pressure to the brake pads generates heat, which must then be dissipated. The quicker you can do both, the more efficient your brakes are. So, having vented discs gives you a greater surface area over which to dissipate the heat. 4-pot calipers allow you to apply more pressure to a larger pad than is standard. Fit these calipers to a standard solid disc and the initial braking effect will be just as good as the vented disc. However, it will rapidly become less efficient as the disc heats up and is less able to dissipate that heat.