I've bought a few things from FT86SF and never had an issue, so can't complain. That said, the knock-offs as legit products had me curious. Found the below on the claims so far.
Looks like the tail lights updated from Valenti to OLM while maintaining the same SKU, price, and reviews.
SKU HTYF86TL-VSQ Feb 2018:
https://web.archive.org/web/20180212...l#.WoG6fp77RPY
SKU HTYF86TL-VSQ Sept 2019:
https://web.archive.org/web/20190808...2013-ft86.html
Current SKU HTYF86TL-VSQ:
https://ftspeed.com/part/htyf86tl-vs...6#.Xx4dQp5KhPY
For the Five:AD spoiler. It looks like Five:AD stopped making the parts and supposedly sold the design/tooling to 3d Carbon at some point. Amusingly with a crappy job of updating the install instructions. I can't validate this as true, though.
Thread:
https://www.ft86club.com/forums/showthread.php?t=116261
SKU FAX61043P-xxx July 9 2017:
https://web.archive.org/web/20170709...l#.WWJ86p77RPY
SKU FAC61043P-xxx July 22 2017:
https://web.archive.org/web/20170722...l#.WXK5BZ77RPY
Current SKU 61043P-XXX-PARENT:
https://ftspeed.com/part/61043p-xxx-...s#.Xx4j0J5KhPY
Oh, and here's a capture of the half price battery tie-down if anyone was curious. No difference on product description, just no longer on sale:
https://web.archive.org/web/20170625...l#.WVASvJ77RPY