I switched from the OEM plugs to the 5992's and like them so far. I am typically pushing about 17psi when running e85, 15 when running straight 91. I sometimes notice a bit of backfire after I changed the plugs, but I'm not sure if it's related to that or the fact that I also adjusted my wastegate at the same time I installed the new plugs (should have waited so I could isolate the plugs better). Nonetheless I love them, my misfire issues when running e85 have diminished (used to misfire at the top of 3rd, or any sudden WOT in 3rd, but may have been blame to the 20k miles I had on my OEM plugs..) I gapped them to 0.022".
'08 E92 335i Pre-LCI | SGM | PTE 6062 VM ST top mount conversion | Alpina B3 TCU Flash | Fortune Auto 500 w/ 8k/11k Swift Springs | 28mm ECS solid FSB | M3 Front and Rear Control Arms w/ Rogue Adjustable Toe Arms | 18x9.5 et22/18x9.5 et35 Arc-8's wrapped in 275/245 NT05's | VRSF V2 catback exhaust | Poly transmission mounts | Solid aluminum subframe bushings | A front bumper that looks like I waxed it with 5 grit sandpaper..