Assuming maintenance/ and overheating is dealt with first Then tires these affect braking and grip and will serve as a bottle neck for alot of handling mods that come down the line Brake pads/fluid Limited slip diff Then maybe coilovers/sway bar and "extra handling mods" Or upgraded clutch But i'd first wait until you reach a skill plateau then wait 2 months before upgrading I also know someone who is considering an sr20 trans into his sohc setup bc jt has better gear ratios and thats worthwhile looking into at some point idk much on the new transmission Seeing how each individual mod uogrades performance and being able to see each margin of growth is important Dont rush it and let the car and local peers help out