The redstuff has better co effecient friction wise at lower temps, so work better sooner, there's something seriously wrong, are they binding at all ?, if they were they could be overheating, the ebc pads with brake in coating can be a bit hairy, I usually take the brake anti rattle shim off the rear of the pad as well, did you need to apply any force to get them in ?, some aftermarket pistons can be a tad longer and so the new pads, new discs can cause a bit of binding, but you'd notice this as soon as pulling away.
tabetha