I think you guys are all mistaking Turbo Lag and Boost Threshold.
Boost Threshold is the RPM at which the turbo 'comes on'. On all these modern turbo engines, the boost threshold is set pretty low. 1400rpm, or so. On Gurgie's 951, the boost threshold was set higher, at around 3000 rpm. A lot of 'old school' turbo engines like the old WRX, the STI, etc. have higher boost thresholds.
That still doesn't change the fact that all turbo engines have a little bit of lag. Lag is the delay between opening the throttle to get full power, and the engine building up enough exhaust gases to spin up the turbo, and then the turbo building up enough pressure in the intake tract to create boost. Every turbo engine will have a bit of lag. It is better now than it used to be for a number of reasons: turbos are mounted closer to the engine so the exhaust and intake plumbing is shorter, and modern turbos are typically itty-bitty therefore they have low inertia and don't take much effort to spin up to speed.
They still have lag, though, especially compared to a naturally aspirated engine, which makes full power at a given RPM as soon as you open the throttle.