Ok I've asked and looked around and can't really get any CLEAR answers of the major difference between an equal length header vs. unequal length. the most I can procure is "equal length is crap!" No real definitive info to back that up. I'm looking into upgrading the entire exhaust system with perring exhaust. I'm pretty much doing everything I can perrin with my soon to be 2013 wrx premium hatch. Just easier that way but I want to know is there a performance difference or just a sound difference and if so what they are