I tried using just the primer (unfortunately, racing white wasn't pretty far from what I needed).  The primer itself is just a shade or two too dark, so I figured I'd kind of try to sand a little off to make it lighter.  That sort of worked, but it ended up kind of splotchy as well: It looks pretty good, but the color is still just a bit off.  If I were going for some kind of weathered or even cell shaded look, it would be fine.  But as-is, it still isn't quite right.  And I found out