Get a 24 or 26m.m. carb, a full flow air filter and a good reed cage.
My first modifications to my bike were Leo Vince ZX, carb, air filter and Polini reed cage, some roller tuning as well and I got a very nice improvement.
The ignition is a very good set-up if you're planing to go far, in this case make a good investment and buy the best you can: MVT, HPI, PVL SELLETRA, Etc.
Regards,