what is original one cfm?
Usually choose the second in 2 ways:
blow out CFM 〉blow in CFM
OR
blow out cfm = blow in cfm
if the given power of 2 fans is same..., only the second option can be chosen, may be i need to buy the second fan as same as the first one...
the orginial one is around 130cfm, 1.3A, buy a 120*120*""38mm"" one can hv lower rpm, lower noise...