A shameless copy & paste from my post over on the Briskoda website but wanted to share over on this forum for info....
This is a bit of a follow-on to my review / 'how-to' on the Porsche 986 calipers :
http://briskoda.net/forums/topic/169744-not-so-big-brake-kit-porsche-brembo-4-pot-calipers-on-vrs/I remain delighted with this brake set-up and the improvement over the standard brakes even with OEM discs was great. However....
DaveB waved a picture of 312mm J-hook discs in front of my nose a while back. I resisted at first as the brake set-up was giving me what I needed but the discs that I had started rusting very early on due to lack of any protection on the metal in the bell area or the unswept area of the braking surface (which was wider than with the stock VRS brakes). This, combined with the kind of curiousity that has cost me £££s already and the good reports that AP and Alcon have had over the J-hook design on different discs made me give in to temptation. This is what turned up:
You will notice that DaveB had kindly powdercoated the bell and outside edges of these discs in addition to the unswept area with my calipers (which wouldn't be an issue with stock brakes). To the left you will notice the old 312mm discs...when I say "old", these were 4 weeks old!!
Here they are on the car
I guess the aesthetic looks of these things are about personal taste. Personally, I liked them although my main driver for buying these was to squeeze a bit extra braking performance...and lose the non-aesthetics of the existing rusting discs. On to the performance....
It is difficult to comment on braking performancewith respect to standard GTI/VRS brakes as I have never tried this and the jump-up with the new calipers would make further improvements a little bit more difficult to distinguish. Generally, I think that they are a tad better in low/medium speed conditions and in the dry. However, where I have felt a more notable difference is when hooning it and in the wet - these seem to react with notably better initial bite and braking thereafter. I guess this is not surprising when you look at the design which is intended to eject water, dust and heat.
Another thing that made me hesitate before buying them was a fear that these things would be noisy - not the case! In fact I can hardly tell the difference from the normal discs. With the window down and some hard breaking, I can make out a very faint 'zipping' sound coming from these discs but only when I am deliberately listening for it.
I think these would be well-worth considering for anyone looking to get some improvement out of the stock VRS brakes particularly with braking in the wet or at speed but for those looking at getting some decent capability out of their 312mm set-up, I think you will still need to be looking at better aftermarket pads or uprated calipers (imho, the standard pads/calipers have no right being on a remapped VRS, MkV GTI and especially a Golf ED30)