You will be doing a massive amount of modification for virtually no benefit. Increase the diameter of the exhaust pipe by 1/4" and install a low back pressure muffler like a glasspack or a steelpack, and you will get as much benefit, or more than the gain headers will accomplish. Most split manifold setups are just for visual effect, something that isn't going to be obvious with a COE
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!