You actually found a couple pretty good dyno plots to compare, had a couple minutes and I'm OK with Excel so I made a couple plots that might be useful. First let's have a look at Torque.
Attachment 839765
When plotted on the same axis you can see the differences in these two boosting systems. The PD makes significantly more torque at the low RPM and then the two systems nearly match at high RPM which we would expect as the peak power of both cars were nearly the same. Now, torque by itself is nearly useless as it is a measure of force, not a measure of work - so in that case we need to reference Power which relates torque to a unit of time - in this case RPM - I have plotted the comparison below.
Attachment 839766
Now the differences become slightly less significant, but we have a useful comparison that can describe the difference in performance between two engines, since you drive in the areas under these curves, that area under the HP curve gives you the operating envelope, the more area, the more performance.
Attachment 839767
So what would make the higher curve faster? For an example, let's take a look at the 1/4 mile data from a Camaro, in this case the car ran a 10.81 and the HP Tuners data log is below.
Attachment 839768
From this data we can learn a lot. First of all you can clearly see that the Stall Speed of our A8 Torque converted at this power level is between 2900 and 3000 RPM. For that period of time the PD SC will be exerting about 285RWHP and the Centri SC will be delivering about 220RWHP (which do you think will 60' better?). Next we find that even though we have an 8 speed close ratio transmission we see drops from 6500 to about 4800 RPM during shifts. Even if we round it up to 5000 RPM the PD is going to have a 50RWHP advantage at 5000 RPM which tapers to equivalent RWHP at 6500 RPM. The power delivered to the rear wheels under the RPM curve will determine how fast we are accelerating. Hopefully by this point you can see why response (which we really didn't cover here) and power under the curve are important.
I quite often hear people say that they prefer the lower HP at lower speeds for traction, but that loss in lower speed power hurts you through the entire acceleration run.
Do you want a fast car? Always take as much power under the curve that you can get and either; learn how to drive it, use the torque management system to control it, or invest in a set of tires that can handle it.
