They have a Haldex electronic rear diff so are not 4Wd until the front wheels begin to slip. If a 320bhp GT4 couldnt pull away easily from a 185bhp GT then I would burn it, I have an Evo 3 now around the 300bhp mark and it wouldnt even fall into the same league as a 180bhp GT at any speed.
I agree Craig at GotBoost is a good guy and knows his stuff, I took a Glanza down there a few weeks back to have the AFR's checked. He's moving buildings at the moment so wont be back open until mid July, I'dd tell him to take it there.