I also bought some S4s on ebay, from an Australian seller and have been pretty upset with the sound quality. The sound is unbalanced with the right bud lacking volume and bass. No problem with the logo rubbing off though. Box is the old style, silver/grey, L-shaped plug, 4 pairs of caps (s,m,l and s flanged) which were in a plastic baggie and a cleaner. Everything other than the sound quality seems legit, which makes me wonder if it's just a defective unit rather than a fake. I figure they probably aren't an authorised reseller, but i was wondering how you tell. There doesn't seem to be anywhere on the klipsch website that lists authorised sellers. Help?
Serial and barcode are 101047109337385 and 7 43878 02129 5 respectively.
I've contacted the seller and I'm still waiting for a response. In the meantime I'm going to wear in the phones overnight and see how they sound in the morning.
Pretty sad about the experience at the moment.