Smithy said:
...NB. Discs come as single items, pads come as a pair...
Pads actually come as an axle set - i.e. 4 pads - 2 pads per disc.
What do you want from your discs? Better heat dissipation or cleaning up the pad where you've glazed them? For heat dissipation, go drilled. For pad cleaning, go grooved.
Cross drilled discs are prone to cracking under extreme use. The Zimmermans i've got on my 8v have been on there for a couple of years now - but the car has spent quite a bit of that time laid up as i've been overseas. It's been road rallied a few times I tend not to be too heavy on brake components anyway.
Grooved discs clean your pads up a treat, but tend to munch pads pretty quickly. Think about how they clean the pad - they work like a cheesegrater.
One thing to be aware of with both types - brake dust will accumulate in the holes of drilled discs, or the grooves of grooved discs. You need to clean the discs up regularly to get the most benefit.
One of these days, i'm going to get around to fitting the
280's that I've had waiting to go on for well over a year now...