Well, one thing leads to another, for a mild street car heads, cam and intake with a better header will net you a fun driver but then a gear change just adds to the fun. After that the water get kinda merky. Biggest thing is to decide what you want from your ride, match that with your ability to learn and work on the ride within the budget you have. There are a lot of combinations here on stangnet so read through some of the ride builds and plan your ride.
Does that make sense? Probably not but not having a plan don't make no sense too.