You can also upgrade your fuel pump and run an aftermarket fuel pressure regulator (Sard or Malpassi) to get more out of your existing injectors.

I'm running a Malpassi FPR and Walbro 400hp with standard 440cc injectors with around 185-190kw atw and would be lucky to see IDCs get in to the 80s.

I'm assuming your running some type of aftermarket engine management otherwise changing injectors would be kind of pointless.