When I replaced my AUX fan last August, I went with X5chemist's recommendation of the TYC fan. At that time, it cost $190 at Amazon (where I bought it from, due to Prime free shipping and getting a discount from them), and see that now Amazon lists it for just $170 (a good deal in my book). It runs so quietly/smoothly, that you can't feel or hear it from inside the X.

The TOPAZ replacement fan , also from Amazon, is half the price, at $95, and may or not be of comparable quality, but given the time and effort spent in installing the AUX fan (especially for an old guy, in direct sun, in 100F+ temperatures), once and done was my choice prompting buying a more expensive fan.
above & below-bumper pieces removed for the install

I think I'd rather go with a recommended/quality part than try another without a recommendation. Perhaps TOPAZ is just as good, but who knows for sure?

I've never had problems with Taiwan-sourced paerts, but have had several with mainland Chinese-made parts, previously. It all depends on the QC given by the "brand" owner, since many Chinesium parts are first-rate, with ones made at the same facility that are seconds, but acceptable to a differnt "brand" owner. I've got some cheap tools and (many) electrical parts from China, but I try to have back-ups for all, just in case. But, as I stated, I'll not be happy to do another AUX fan install, anytime soon.

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01 BMW X5 E53,3.0i-5L40E, 7/13/01
topas-blau,Leder-grau,"resto-project car"

Here:
14 Lexus ES350,3.5L-U660E
09 HHR Panel,2.2L-4T45E
04 Chevy 2500HD,6.0L-4L80E
98 GMC Sierra 1500,5.7L-4L60E

Gone:
66 Chevelle Malibu 2dr ht.,327>441c.i.-TH350>PGlide/transbrake
08 Cobalt Coupe,2.2L-4T45E
69 & 75 C10s,350c.i.-TH350
86 S10,2.8L-700R4
73 Volvo 142,2.0L-MT4
72 & 73 VW SuperBeetles,1.6l-MT4
64 VW,1.2l-MT4
67 Dodge Monaco 500 2dr ht.,383c.i.-A727
56 Chevy 210 4dr,265c.i.-PGlide