It's tough to get really quiet with a tbird. About the quietest 60mm that will do the job would be a sanyodenki pico ace- KDComputers carries them.
Might also get acceptable results using a 60-80 mm adapter and something like a M1a panaflo- set it up pulling air thru the sink, exhausting away, the fanadapters seem to work better that way. Download and use Motherboard Monitor to test it, don't let the temps climb above 65 centigrade, worst case scenario....
Be sure that it's the cpu fan that's causing the trouble, also try unplugging the front fan on the Enlight- pretty useless unless the box has been modified....