As for seals, as above, varbon apex seals are more likely to chip on used housings that the standy tips, standy tips heat up and arnt soft but do take to the shape of the housing, carbon does not, thats why i'm just replacing my tips with 2mm 2 piece mazda steel 1s (if it aint broke, dont fix it) but in saying that, ive heard that the steels like to break/chip at high rpm