Spetz, from my seat of the pants observation the headers gave me "oomph" 3 times across the whole rev range. the first was aroung 2000-2500rpm then the second one at 3500-4000 , then between 5000-5500 (with the 2inch open exhaust ), so i think it gave the car performance improvements throughout the rev range.

btw my long term plan is to put an m104 under the hood, but, right now im still gathering the funds, maybe in a year or so. so this is just a lil exersise for fun while waiting for the bigger motor swap to come.

cheers mate