I am on my 3rd set of Elkas (Rincon, TRX 450R and Can Am Outlander 800) and can tell you once you get them dialed in you will love them.
The sets come with everything you will need to mount them.
Depending on what stage you got will depend on what adjustments you will have. The stage 5's are the best (450R) also had the stage 2's (Rincon) and now the stage 3's on the Outlander.
Take your time setting them up, play with the adjustments, this will let you get a feel for them until you find the exact setup you want. I'm still doing this on the Outlander's Elkas.
Will be interested to hear how you like them once you get them adjusted to your riding habit. Have a set on my wish list for the XX but too soon according to the wife!
Good luck and enjoy, they are the best!