It's good to see something entirely different in Entry #2. It looks very pro. However I think the design could do with more edge to reflect the business (Premium service, technical superiority, high hp result) and the target audience (See brief for notes on the target audience).
In reference to entry #9, the - is not required. I believe I made an error in stating the name of the company as X-tune, X Tune and Xtune are also trading names. I like the colour. It's good to see some variation on the X, however I prefer edgier lines rather than curves. Thanks!
I like #21, however maybe the stagger in the X makes it look too much like a K? I'm not sure if it's me spending too much time looking at theses logo's or if infact it is easy to interpret it as a K rather than an X. Good work!