Technique was.... don't break my car lol. Gear changes were quick but they weren't slammed in. For the last few year at Banzai I've always kept the ESP on and been a bit rough with it, tried it off once and just it 'scudded' off the ground as the wheels spun and bounced , but this year I decided to do all the races with it off and just progressively put the throttle down in 1st gear, once your in 2nd its ok. I wasn't fussed for reaction times I'd rather get it as smooth as possible, keep my bloody clutch! and then when its in 2nd hoof it. ,....worked lol (except on the modded ST where I got too jumpy and pushed a bit hard, lighting up the rears lol). You just gotta resist the temptation to plant it in first, you put it down a bit, see how it feels and apply pressure from there at whatever rate keeps the car movin' Wee learning curve for me but I managed it not bad.
Oh and in terms of being brutal it'll always feel like that in the Z, there rough feeling things to do such starts with. I held it on the handbrake and either tapped at the throttle or if I thought there wasn't long to go found a bit of bite, dropped the handbrake and went... but didn't slam it down, almost as if you were picking away quickly. Wanted to keep that clutch so just relied on the power after taking off to get me through.