SP fans are made for pushing air through thight spaces, like full HDD cages. I'd try if you want to use them as an intake.
However, judging by the amount of harddrives I'm guessing this is a home server of some sort? If the components inside don't need that much cooling (Like an i3 with some RAM and no(or a low-end) GPU) I'd recommend you to flip the airflow path around and set the rear (and maybe top) as intakes.
You can then use the front as an exhaust. That way you blow all the hot air from the HDDs into the case, but you'll pull it out the front.
If you do it that way, I would recommend you the buy a dust filter of some sort for your new intake fans.