I agree with Evil. I'm running an S4 and I was reminded of this 'lag' when coming back from a week in FL where I was lucky enough to be pootling around in a Corvette Stingray and then 5.0 Mustang. Now the Corvette made the Mustang feel slow, but both of them had much easier throttle modulation and pick-up from standstill. My take on the S4 is that there is turbo lag but also engineered 'softness' to acceleration inputs in D1, and it's likely if you're just in Comfort setting on the gearbox that unless totally still it might try and take off in D2, rather than dropping to D1. Both of these facts mean that you're unlikely to feel totally in control when you make that initial prod of the accelerator to move off. This is then made more startling when you shove your foot down in the 'OMG, OMG, gonna get sideswiped!!!' moments moving across oncoming traffic on a roundabout (for instance) and the car suddenly lunges forward and makes you look like a novice who just passed his test yesterday...
I always have stop/start disabled (part of my start-up routine!) so I know this doesn't come into it. And yes the Corvette and Mustang are big atmospheric V8s, but its their reaction to the first instance of accelerator push when at a standstill that reminded me of the S4's 'reluctance' to move away once I got back to the UK. Still love the S4, but you do need to drive around this and be aware of it when 'nipping out'.