I had absolutely zero issues with E85. And for the price/quality of the stainless power headers, I highly recommend them. Fit and finish was excellent. I installed my own and did it on jackstands in the garage even. Pretty sure I did an install write up. I did install the big daddy O2 spacer mil eliminators on the rear O2’s for safe measure. Pretty sure they were like $780 from lethal shipped when I got em.Kooks are definitely expensive since they're the best. I was planning to go with either Corsa ($1200) or Stainless Power ($1034) which were within my budget. I'm leaning towards Stainless Power based on feedback from @sabtaj1 and few others. He got them last year and had good things to say about them.
@sabtaj1, did you have any issues with O2 sensors running E85 on SP headers ?