I think it’s pretty well understood that a quality aftermarket exhaust system will provide improved sound, airflow, and just plain ol’ aesthetic appeal. I’d like to focus on the airflow side of things. Where exactly is the improved air flow coming from? Are the head pipes simply a larger diameter than the OEM pipes? Or is the improved flow mainly coming from scrapping the restrictive factory muffler/cat? Now I’m aware that company’s like V&H and Cobra design their head pipes to improve exhaust gas scavenging and things like that. That being said…IF the majority of improvement is coming from replacing the OE muffler/cat then wouldn’t the Cobra Slip-on yield similar performance gains as a full system when coupled with an air breather and fuel processor?