You might try to snag a pair of Zu Mission ICs on ebay. I got two different pairs for a bit above your $100 limit (each).
Can I upgrade my IC cable for $100?
I have put together a desktop headphone system recently that consists of a Musical Fidelity A5 CD player and Mapletree Audio Ear+ HD amp. I and using a DH Labs BL-1 IC cable between the two. The sound is very good but could be a little sweeter in the highs. Can anyone recommend a cable that will better the performance of the BL-1 ICs for a budget of about $100 new or used?