Hardware hack-so was this a good idea?

On A media center pc I built form old pc parts (6gb ddr3 Athlon x4 640 gtx440{fanless} blue ray player and netflix box) I changed the fan in the power supply with a cougar 120mm fan because the noise from the stock was just god awful. I ran the 3pin plug out of the psu, from the same hole as the conected cables, to a fan controler and im just keeping it at 70% power. I know that I just killed any warranty that the psu might of had but im ok with that.
so what this a good idea? and I will be changing the power supply in a month or 2
on a side note the fan I took out is made by fujian

This should be fine, just be wary of the temps, PSU's tend to run a bit hot in general.

70% should be fine though.