Seeing as how the wife and kid are with me 75% of the time, being loud is secondary to sounding right. Build is in a Mazda 5. Currently evaluating if I could stuff something under the 3rd row or go with the original plan, in the far rear,that I saw someone had done on the Mazda247 forum and liked that. Really wish I could get a 10 or 12 in without taking any usable space up, just not happening.
Both of those 8's look like they would fit the bill.
Amp will be last thing to be purchased. May have my old OPTI4100 to use bridged on the sub and stereo to the fronts.