Turbo Lag?

[DMC]

Hey guys, this is kind of a strange question, and its difficukt for me to ask it how i want, so please bare with me.

On turbo cars they have what everyone calls lag. How bad does lag effect the car?

Is the lag up until the turbo produces any "boost" at all? Assuming the answer is yes........

Like through when the turbo begins to spool till when boost kicks in, how much slower is the car than it would be through the same range on the non-turbo version of that car?

Not sure I explained that too well, so lets say i have 2 identical 240sxs. I put a big turbo on one. The turbo doesnt begin to make boost till 3000(an exaggerated number). Both cars race and both shift at exactly 3000 rpms. How much slower will the turbo one be?

Anyway if you can kinda get what im asking any help would be nice! Thanks!