I just picked up a WIX 51334 oil filter which said Made in South Korea on the package. It looks like production of this filter has moved to the Mann+Hummel factory where the OE filters for Hyundai and Kia are made. Construction looks nearly identical, except for the base plate which has 6 holes on the Wix vs 5 on the Hyundai OE filter. The gasket type is the same between the two filters. The bypass valve design looks the same as the OE filter, just without the Hyundai logo stamped on it. I'll plan to cut this open later this year after running it for about 7,500 miles and compare to a used Hyundai filter.
Pictures are attached with it next to the Hyundai filter. It would be interesting to know the efficiency numbers between the two filters to see if the Wix still retains its typical high efficiency numbers. The Hyundai filter is thought to be fairly inefficient vs. premium aftermarket filters, but a lot of this is based on an old video about counterfeit filters and the OE part number has been revised a few times since then.
Pictures are attached with it next to the Hyundai filter. It would be interesting to know the efficiency numbers between the two filters to see if the Wix still retains its typical high efficiency numbers. The Hyundai filter is thought to be fairly inefficient vs. premium aftermarket filters, but a lot of this is based on an old video about counterfeit filters and the OE part number has been revised a few times since then.