fg xr6 turbo ute

Hey guys. I just had some work done on my 2011 fg turb ute. Cat back herrod exhaust with high flow cat, bigger injectors, and custom tune on SCT handcontroller. Running 15psi I got 273rwkw (was only using 95octane fuel, he thinks higher with 98) and 257rwkw on 12psi. Do you think the 300rwkw region is achievable on 98 octane if I move down south with these settings? I think the Darwin heat may be costing me some ponies?