The catback exhaust systems have been talked about over and over and over again. With the greddy evo exhaust the piping in 60 mm. I think this is about 2.4 inches. Somebody correctly me if i'm wrong. But anyways, some people are saying that this piping is so large and will hurt your cars performance because I don't have turbo or what not. But others are saying that you will lose a hair off low end but it will make the top end faster. I just want to know the truth. Is this going to slow down my car. Is the greddy evo a dumb exhaust to put on a d16y8 engine. Is this an upgrade from stock? I'm just sick of reading different stuff and i'm not knowing what to believe...