FWIW When I installed the Kelford 272s on my 8 This weekend it knocked my fuel trims wayyy out of whack at Idle..> I bumped idle up to ~1000 RPM and tweaked the MAF Comp a bit and everything came out happy... I've driven about 500 miles on them so far though and they have excellent street manners..and the stock 16g pulls noticibly stronger to redline vs with the HKS 264s I took out..

I also did the Valve Seals and MAP Ultimate duty springs (with stock retainers) at the same time.