How important is box volume on midrance response?


I'm looking at 299-246 which is a Vifa 5" Wideband driver at 4ohms. I'd like to put this in a small kickpanel in the car, there's going to be an 8" in the door crossing over at below 1khz most likely and I"m going to crossover to the dash tweets only as necessary depending on the full response of this driver.

Playing around with WinISD online, if I put this driver into a sealed box that was too small I got a midbass peak and a pretty high qtc, something like 1.2. So my question is this, according to WinISD the peak due to a small box was below my crossover freq from the 8" in the door and above that it was theoretically flat. How would this sound? Is this a bad idea or should I just try to find a better driver with low qts and vas that'll run better in a small sealed box?

Thanks folks,