I wouldn't suggest putting in Panaflo fans, they are made for the case and not a power supply. The fan in your power supply was meant to be in you power supply and is probably loud for a reason (it probably needs a lot of air). The Panaflo L1A and M1A fans probably have too low RPMs for your power supply, and the H1A is probably just as loud. Plus, Panaflo fans are meant to be case fans, they aren't reliable enough to be on a heatsink or power supply.
If you do change the fans, be very careful. Sometimes a charge can be stored up in there that can really do some damage.
If you want a quieter power supply, I would recommend getting a Enermax 330 Watt Whisper series. It is probably the best quality and it has 2 very quiet fans running that you can barely hear. You can get it at directron.com as well as many other places.