Decats make a hissing noise when the load is taken of around. 3krpm, if it's a daily driver then go for hfc's. I wouldn't recommend decats for a daily as the risk is much higher of getting emission tested.
Scorpion is slightly more raspy under load than the oem but videos online do not do it justice. Try and tag along to a meet as there will be loads of exhausts on show. Scorpion comes with a lifetime warranty also.