Headers raise the underhood temperature 100 degrees, burn you whenever you work on the engine, and only last a few years (vibration cracks, rust).
Without a hot cam, headers add no power.
Either way, don't join the 2 exhaust pipes, leave them separate.
BTW: half of all engines & cars sold "have a mild cam".
No, they don't, it's just what people like to say & hear. A cam hot enough to make a difference is a PITA to drive in traffic.
