yes, i am told it is not exactly great to change the polarity of the fan but I am not competant enough in that area. Just unhook the clips, flip the fan(undo grill if necessary) and plug in, and you got it goint the other way!
Some of the Alpha coolers seem to work better with the fan sucking instead of blowing. I have a GlobalWin FOP and experimented with the fan mounted both ways. With my system, it cooled best with the fan blowing onto the heatsink. Also, if that Delta 38 fan is too loud, do what I did and mount a 80mm fan onto it instead. Much quieter with as much if not more air flow (depending on which 80mm fan you use).
The FOP-32 uses the same HS as the FOP-38. A long time ago, I flipped the YS-Tech fan on my FOP-32 to exhaust. CPU temp went up 3C. I even fashioned a shroud ala Alpha, but it did not help. This experiment was done with the case open to remove case ventilation performance from contributing to the evaluation. That was my experience.