Yea I have seen a lot of people running open header on motors like gsr,b16 and sohc,They don't usually mess up at all. Well then again the people I see running open header usually are spraying anyways.So of course you will have damage from that if your car isn't tuned correctly but my friend took his exhaust off his sohc.And it felt alot better from the stock dented and clogged exhaust.And he drove his car for over a year like that shit sounded so annoying though.