Glad you managed to get your Custom 3's sorted out. I think the Custom 3's and the x10s probably dont have studio quality accuracy to it, but then again it doesnt really bother me too much as they are really fun sounding earphones. If you want flat response, you would probably look into something like Etymotic. But I personally think that music is meant to be enjoyed, not analyzed. But it's all just personal taste of course, if you enjoy it, then that's all that matters.
Anyways, as for my x10, I dont think I will be as lucky as you. The strain relief on my x10's literally split in half and they have not been abused at all. I have always been a huge fan of the Klipsch sound and I own alot of Klipsch products, but the x10 is a HUGE dissapointment for me. Although they are the best sounding iem's I have, I cant believe how terrible the build quality is considering that they are the top of the line from Klipsch. I really hope someone at Klipsch is paying attention and fixes this problem. I understand that without a proof of purchase, I am probably out of luck as far as getting my x10s replaced/repaired but I wish Klipsch would print a serial on their iems or something so that a warranty replacement can be issued even without a receipt. Shure does this with their products and they have been known to have pretty amazing customer support (had my old Shure e2cs replaced under warranty no fuss at all and without a receipt).