this is why i'm not in favour of them. they may give a great short term solution but in the long run they'll warp your discs due to increasedheat & gas buildup, wear them out much faster and can fail when slightly wet. there was a discussion a while back about pads absorbing moisture too,.. which carbon & carbon metallic pads do.
Example: I had ferodo pads in one of my golfs (daily driver) and a full AP racing upgrade in my other identical golf (semi-track use), surprisingly the one with ferodo pads stopped better throughout the normal heat ranges, but on heavy/track use the ferodo ones faded VERY fast whereas the AP racng equipped car kept on going and going and going.
Now i doubt anyone is going to be braking as hard and as long as i used to on the Nürburgring, Monza, Silverstone or Castle Combe & the roads here don't provide enough grip for upgraded brakes to work effecively (too much braking for the available grip),.. this is why i suggest that for PK/street uses we stick to OEM pads.
