Welcome to SPCR!!!!!
180mm is a very peculiar and no that common, very few options out there, while on 120 you will find the best fans atm, and even so there are some 180s that are not 25mm like most fans, so you are limiting lot the options out there.
A lot of people find the Silverstone AP181 too noisy, i used to use a TJ08-E and activly participated on the owners thread on OCN, but its a really good fan in term of performance, the problem is that above 500rpms becomes noticible (maybe even lower for some), could be the mesh as well, but a lot find it noticeble, and thus some look out for some alternatives, some people prefered the Phobia 180, might be less noisy, but i never tried it says it is. But on OCN most that made the change say its better.
Personally i think the silverstone has a great fan, even SPCR liked it on the TJ08-E review, hell even on the FT02 review, but the problem is that its too noticeable. In persue for a fan that could lower more i tested the AP182, that can be dropped much lower, in case you are interested check Taming the beast, Silverstone AP182
So either AP182 or the Phobia is what i would suggest to consider, if neither is to your liking, then go back to 120s.