It all depends on where the limitation is - something that I don't think has been conclusively established so far.
The most cogent argument I saw built the case that the power limiting comes from a computer model for the temperature of the drive motor rotor - one of the few parts that can't be easily instrumented; the testing indicated that the limiter showed up the same way regardless of the actual temperature of the pack and motor at the start of the test.
If you accept that assumption, the P85D should be at least as good as the existing cars and likely far better, depending on how it is driven. With two motors being cooled, it'll be able to handle the maximum power the P85 had for a lot longer, and recover faster. OTOH, if the extra power the D has is used regularly, it might get into the same limiters at a similar rate (but the car would still be going faster because you're using more power to get there.) It would still seem like it should recover a lot faster at a given power level with two sets of motor cooling (assuming the rest of the cooling system can keep up, of course.)
It's too bad that the beautiful screen full of component temperatures I saw in a couple screen shots is apparently only available to Rangers. It would make figuring this stuff out so much easier, and might open the door to ways to improve the performance...
Walter