19 years old, mustang enthusiast, 2012 v6 owner, and Saving for a 5.0 GT. what's the main differences between the roush stages? And whats the cost of these over the Boss 302 mustangs? I'm planning on stepping up when I'm 25 since my insurance will be lower. Just want to know what to save for? I'm just curious and I want to know more of the v8 world. Feed my brain, thanks in advance.