Thank you all for the excellent answers and advice as I've been thinking about this a lot lately.
I think I'll take BGTV8's advice and practice "feathering" the throttle more. I guess I'm a bit slack and too used to using it as an "on/off" button.
I do have I think a pretty good suspension setup now with every part upgraded (except for front camber arms). Earlier this year I had MCA Red (custom valving) coilovers fitted (true coilover in rear now) which replaced my BC-BR coilovers when the car was lowered and have had it raised again to optimise the suspension travel and adjustements.
I'm using Yokohama AD08R tyres but the standard 370Z sizes. It was not possible to get wider tyres to suit the Z in Australia due to our small market here without paying stupid prices. They're just not normally available here as they are in the US.