E46 M3 Road/Track brake pads

I had the car checked by the local independent BMW specialist who looked after my previous 330Ci.  They said the front discs were lipped but within manufacturers tolerances.  The brake fluid needed changing but it should be good for one more track day and was not urgent.  Unfortunately there was no time to get the fluid replaced.

The braking system on the M3 did not perform well today!  

I completed 8 track days in my 330Ci without a single braking issue (or any other mechanical problem) and my EBC Greenstuff pads used to last several days, so I presume I do not have a driving style that is particularly heavy on brakes.  Today I initially went out for a warm up lap, 3 quicker laps (although not full pace) and a couple of miles of cool down before returning to the pits.  The front pads were gently smoking and the discs were clicking loudly.  I gave them half an hour to cool down and repeated the exercise with the same result.  After another 20 minutes or so I had my usual instructor session, which was longer and faster and didn't include my usual cooling lap.  As we sat in the car the smoke rising from the front pads was all too apparent; the brakes were more or less on fire!  Also the next time I started the car in the garage the brake pedal dropped to the floor, so I presume the fluid had boiled.  It wasn't safe to continue.  The brake fluid issue is easily solved but clearly there is a general overheating issue.

I met a CSL owner in the pits before the off, who predicted brake failure within a few laps with standard set up and said I needed compete AP systems all round, which is what many Forums say.  Unfortunately this is a very expensive option!  I guess replacing the slightly worn front discs with DBA ones paired with the right pads and brake lines might be a good compromise but could slightly worn OEM disks really account for such poor heat dissipation?

To update the thread above for those interested, in the end I went for the AP Racing front big brake kit. I also put new OEM discs on the rear with EBC Yellowstuff pads.  I went for this option as I wanted to be able to use the M3 for a similar number and duration of circuit sessions on track days as I had been able to enjoy with the 330Ci (otherwise the upgrade might not have been worthwhile) and it seemed to offer the best chance of this. 

The AP Racing BBK performed well on the first outing at Bedford GT circuit, which is quite heavy on brakes e.g at the end of the main straight I was braking from 130+ to 65 mph and at the hairpin from 100 to 30mph each lap.  

The kit came with their own APF404 compound pads (they have recently started supplying their own branded pads). Despite careful cooling down laps, I was experiencing brake judder by the end of the day.  Hoping it was just a case of pad deposits, I ran like this at the club track day at Donington.  Brake performance remained good but the vibration also remained unchanged.  AP Racing told me to send the discs back to them for a light grinding, to get them back to true.  They did this free of charge.

My local independent BMW specialist had inspected the discs and diagnosed warping but in fact the issue was pad deposits.  AP Racing suggest I use Ferodo DS3000 pads (or Carbotech XP10) to avoid future problems.  I would have thought DS2500 sufficient unless I am unusually hard on the brakes. Furthermore the Ferodo UK importer website indicates that is the only compound they make for E46 M3.  AP insist DS300 is available but I can't find them, so I think I'll go with DS2500.  

Any recommendations on a supplier?