Just FYI, the nylon cage is used on Champ Labs made filters for AC and other
mfgs that sub contract them for filters. Wix used to make the SuperTech filters, (white paint)
but all are now Champ Labs. Even the fiber end caps that some have a hissy fit about, are on some
Wix, AC, and other filters as well. they are decent for the purpose and work fine.
Before the ST filters were made by Wix, they were made by Champ Labs, black can. The ecores had polyester endcaps and many of the larger filters used a combo valve. The smallest ST filters, 7317/6607, 4386/4967, all kept classic Champ Labs construction, metal caps, louvered tube and separate dome bypass. Not sure why that the case, but it was. 'Afaik', the original ST OFs (black can) were made by Champ Labs. So now really just come full circle. The Wix made ST only around a relatively short period of time. I remember they consolidated the 9688 application into the 7317 filter application size.
I prefer the newer MP Super Tech, all with dome separate bypass and metal caps, like topic. Yes, MP ~$2.50 more for the silicone adbv, worth it 'for me'. Pass on MP with black adbv though. I thought they might have brought back the ST7317 w/nitrile adbv with new Champ Labs ST, but not seeing it on WM .com now. Some current ST series use the original ecore design, polyester caps with combo valve.
As for ST7317 never being an ecore, that is correct, as noted they have 'classic' construction. However, the ST7317 did exist, I cut one open ~12 years ago (linked) to check the louvers when Champ was reportedly having some issues with them. As an aside, some members might recognize the first commenter after the OP. 😉
This is the ST I purchased primarily to look at the new ST centertube design, and posted pics in this thread. The filter seems well made with an interesting seam/joining pleat as shown in the second pic. The base plate in quite heavy, especially compared to the can thickness. Centertube...
As for Wix OFs having/using/making ecore tube with polyester caps, 'pretty sure' that never the case. Yes, ACDelco used/uses ecore tubes with polyester caps because they have been made by Champ Labs for a long time. But, ACD ecores for GM vehicles with filter bypass, never spec'd combo valve, always separate bypass. Afaik, only Champ Labs has used an ecore design.
Seems I got a little carried away with Super Tech oil filter history lesson.
But, saw some comments wanted to fill in the pieces for readers of this board.