All the info is on the vendor websites.. however its easy to cheat the dyno numbers. So the only thing you can really measure is price and weight. I can tell you from my experience, the Graves exhaust is really light, sounds amazing and adds allot more torque. Add the Power commander and it turns into a beast. Its the most expensive one that I know of, but for me performance has more value over style and brand name. You have to first decide whats more important for your money, then you can make a healthy decision.Can somebody put togather dyno numbers on all the exhaust systems that are out and compare price,power and weight ?