When I got my car mapped from the standard 220bhp to 340bhp, I totally destroyed my nearly new standard discs with standard WRX MY06 4-pots (warping and heat fracturing!). Even with the standard power, I ruined a set of discs, but with the remap etc. the destruction was night and day compared to the first time! I now run Brembos (from STI MY04) which are not only much more efficient, they are way more durable as well. The disks I got with the 2nd hand kit were 2 years old and had already seen track days. While they are past their best, there was no destruction. Therefore, buy the best you can afford, especially if you're going to be tracking the car. My tuppence worth.