It is definitely not "normal", but seems like a common problem. I know exactly how you felt. I had the exact problem on my 2004 3.0i when I first got it 3 years ago. My dealer somehow mysteriously fixed it during one of several visits trying to rectified the problem, though, they claimed ignorant on the issue. I suspect that they either reset the adaptive throttle or downloaded a software upgrade for it. Now, it is very linear, as it should be, although, still not as responsive as I would have liked with a direct link. But it is 100% more drivable now.

I would make them fix it first prior to taking delivery. It's not much fun driving with that throttle delay problem. Definitely very dangerous as you would have to anticipate on what you're doing all the time...up to several seconds in some instances...not a fun thing to do. It's so bad that I had almost wanting to get rid of it! But luckily, they've fixed it and I've been extremely happy with the results!