I would leave it alone, but if you are determined to do that, make sure the Panaflo will fit. It's not a 25mm-thick fan, I believe it is 38mm thick and I can't picture it fitting in there (I have an Enermax 350 in the fleet). Also, keep in mind that the Panaflo fans you're thinking of are not ball-bearing fans, even though they are very nice... there might be an advantage to the ball-bearing fans for sheer longevity.