What’s the best Mustang model to mod for street or track performance?

[v8ismyheart]

Alright Mustang fans, I’m thinking of getting into mods, but I’m not sure which model is the best to start with. I’ve heard the GT is great for street performance, but what about track use? Should I go for something older or stick with the newer models? And what mods should I prioritize—suspension, engine, or something else?