What elka's are you comparing to? If you get an elka with similar adjustments as the ds450 shocks I would still think the elka's would be better. Of course they will probably cost more too, but they should fit correctly and not need to be modified.
I guess if you have a bunch of money burning a hole in your pocket buy the Elkas. I'm doing DS450X shox up front and having the rears revalved and sprung for me. I've done this type of thing with all my stuff other than my street bike and have had great success. I save a lot of money also.