Your 100% correct in saying a flash tune won't cut it, esp if you really want to push the limits of your machine.
I would strongly recommend you have a look at the CPE Standback as it was specifically designed for the Direct Injection engine. I did my research when i first started and the standback was far superior to the interceptor in regards to features and how it's tuned.
Not to mention it's pretty good bang for buck and you don't have to cut wires cause there is already a PNP available for it(makes demodding it pretty simple).
If you want more info, have a chat to Aaron from MPS Garage, he was the bloke that convinced me to go down this path, and i'm damm happy he did!
CorkSport FMIC with Cold Air Induction, , Cork Sport Cat Back, CPE Standback with PNP, TurboSmart BOV, Custom Highflow Cat with CorkSports Downpipe,Pauter Rods, CP Pistons,ARP Head Studs, BIGGER TURBO COMING, Pre-ordered a Stage 3 CPE Engine.