i haven't got as many cubes as you but i'm building my own custom headers. was up till 11.30 last nite welding these together. 2" primaries stepping up to 2 1/8" before going into 3 1/2" slip on merged collectors. they're not long tubes by anymeans & we don't have to run muffs. still have to weld on the pyro mounts & the CC extractor flare but i feel these babies when finished will help my gases flow & maybe nett me a few more ponies.