The SPARQ measurements themselves have been discussed a lot here - do a search.
I find it kind of amusing: my son has been through several showcases where SPARQ measures were taken, and he's never once had any coach ask about his rating. Granted, he is a catcher, so it is not as relevant as perhaps for a CF or SS.
But I continue to think that at best, the SPARQ rating system has limited applicability to baseball, and sheds very little light on who can play the game.
As an auxillary item of information, perhaps, it is worthwhile. It does measure certain aspects of athleticism.
But my view is that if you took 100 kids and simply watched them run them the length of a football field, afterwards you could probably line them up 1-100 and come pretty close to estimating how their relative SPARQ ratings would line up.
So spending a half day of every showcase getting a SPARQ measure seems like a waste of time. Especially since every kid has already done it several times at other showcases, and the scores probably vary very little from one day to the other.