what is the main difference between headers? a 4-2-1, 4-1. i know the physical diff and design intentions, but what is better for a n/a engine with mid level build up? i have heard a 4-1 produces higher end power with high rpms, compared to a 4-2-1 which has a better overall power band with hp and tq gains in the mid level rpms. also stainless or ceramic. which last longer or is better? i have a 96 ls teg