I replaced the Nidec TA450DC B35502-35 235 cfm fan and the other mystery fan with 2 of these Sanyo Denki 109R1212H1011 fans pushing around 102 cfm each and under 43dbs the units purr like kittens and still keeping the temp under 68c, average is 55-57c. Got them off Ebay from dealer in Cali. there is a 150 cfm model but then you back at the 56db noise. 
http://www.ebay.com/itm/281311612245?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649