You mean amps, of course.
Selecting amps is always tricky because they are in the middle of the chain. Most people prefer neutrality in amps as well as other characteristics. Everything begins at the source, so if your source (player) has a colored sound sig and you're not entirely happy with it, an amp may not be able to "correct" that issue.
The most resolving, arguably one of the highest overall quality portable amp you find on the market today is the balanced RSA Protector. So it may compliment your Sony X when driven from a LOD cable, but you may also be able to achieve better results by putting that money towards a pair of JH13 Pro customs, which can be driven directly out of the HP-out of the player and experience far better overall results than trying to amp universal-class IEMs.
There are a lot of variables to consider and none of them cheap, so there is a lot to consider. You may want to check if there is a local Meet in your area so that you can mingle with fellow head-fiers and have a chance to audition some systems, headphones and impressions before spending a bunch of money. Welcome to Head-Fi and sorry about your wallet!