I drove an S4 with the same engine when it came out about a year and a half ago and it did have that lag. Search the S4 section of this forum and you will find discussions about it. That does not mean they have not fixed it, but there were complaints about it early on. I have not followed that forum much since then.

I have the 2019 A6 55 TSFI engine. And there is no such 1-2 second lag. It does have a small hybrid engine where the engine shuts off at stop lights and during coasting on freeways for fuel economy, and you do notice it switches on the engine the moment you release the brakes. But it’s instantaneous and has no lag. But of course, test drive it yourself to feel confident before your buy.

And by the way, there is an option on dash to disable the engine shut off while car is at a stop. Update: I drove a 2019 Q7 for last 3 weeks and did notice a slight delay on occasion. It was very rare but it did happen a couple of times — particularly when starting on an incline.

Considering that Car and Driver just did a comparo of the new A7 (same engine and actually a little heavier I believe) with the new CLS and clocked it at 4.4 seconds to 60mph I think it’s safe to say turbo lag is a non-issue

I haven’t noticed any lag in my new A7. However, I’m being a good boy and observing proper break-in period so haven’t nailed her to redline - yet