Doctor Rob :
AHH you are correct lol.. didn't pay attention I guess. my bad.. but 9% faster for $30 I would do it. some games its MUCH more then that.. others about the same.
but it would also depend on the exact model / brand.. as some are OCed from the get go and others are not etc..
Also, i highly doubt you will find one within a $30 gap difference as the MSRP alone is a $50 difference on the FE editions. Currently aftermarket cards are well over $50-$70.
The FPS difference, even if its 2-3 or 7-8, Still ain't worth it as both of these cards will become obsolete and reach the end of their cycle at the same exact time of this universe.
Most GTX 1080 owners are quite upset and offended by the release of the 1070 TI anyways; which is why they defend the performance gaps so emotionally.
Its bad enough that the GTX 1080 TI replaced the GTX 1080's MSRP and offered a massive increase in performance.
Now the 1070 TI comes around and makes the GTX 1080 an even worse buy for gamers in Price to Performance ratio.
In the last Nvidia Series the GTX 980 didn't take this much of a beating. It's unfortunate that the GTX 1080 in this series had to suffer this much.
Just be glad you're not one of those users that bought a GTX 1080 around the time it was being bullied and pushed around with disrespect.