So I just got my first car back which is a 03 mustang 3.8. After getting it up & running again I decided I wanted to go ahead & upgrade it. I used to work on cars with my dad so you know, but seems like I keep running into issues. I ordered all the parts which are a cold air intake, manifold, throttle intake, coil pack, and dual exhaust. So far I've been having some setbacks, first I found out that my car cant have dual intakes because the gas tank is too big. Now I'm figuring out I ordered a manifold for a 4.6, not 3.8, they look the same but I'm not sure if they're interchangeable. All of this and I haven't even started the project yet, can anyone give me some helpful pointers.