I have searched over many posts and have been doing some research on trans. and rear end fluid. I have come to the conclusion of using Royal Purple Syncromax in the tranny, but I still dont know about the rear end. I have found it unclear if running synthetic is bad and if you need an additive or not for the limited slip. So what should I look for??? My stang is my daily driver so I want performance with longevity. I know many of you have different opinions on what to run, but I am mostly after the "this will wreck your rear end if you..." help. thanks a lot guys!