Ok I had my stage 4 kit put in from agp, the numbers are decent that it is putting out, its tuned at 19 psi, on 93 pump gas. My dyno looked like this.

It is 337 whp, I know i can get more out of my turbo. So my question is where do i go from here? What do i purchase next. Any suggestions?
Here is my list of mods currently:
Agp t3/04 turbo
Turbonetics external wastegate
Agp cold air Intake
Hks ssq blow off
Afc 2
Walbro 255iph high pressure fuel pump
Agp 750cc RC injectors
Turbonetics variable boost controller
Agp hard pipe kit
Quick whips Race front mount intercooler
Agp solid motor mounts
Billy boat 3inch turbo back exhaust

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AGP stage 4 Turbo Kit, AGP Cold Air Intake, AGP Fuel Kit,Turbonetics Variable Billet Boost Controller, bwoody catch can, Walbro 255lph high pressure fuel pump, 750cc injectors, HKS Super Sequential, AGP hard pipe kit, Turbonetics external wastegate, AFC II, Quick whips fmic, billy boat turbo back 3' exhaust. 18' Hp racing evo rims. Custom powder coating by bwoody performance.
396whp / 368 tor "Evo Killer" on race fuel
updated and tuned....