As long as you're not maxed out on your 5V rail, it should be fine. I had similar problems with my Pana slim drive w/ the Centrix USB2 enclosure/adapter. My USB cable run was over 6', which didn't help. From a previous thread about this drive, someone found the specs on it and I think the max draw at full speed is around 2.5A, so make sure your 5V rail has headroom for this.
Since I didn't feel like running yet another long cable from the back of my car to the dash (for +5V) I just put a standalone 12V->5V regulator and have it running from the switched ignition source. Works like a champ now