FAST system in a vehicle

[901Fixer]

I've searched to no avail. I'm designing a system for a Miata door, hopefully that will need no additional sub-woofer. I can go as big as an 8" and also a mid-tweeter.
A member on Miata.net has used an Aura 2" and Dayton SLS8" with good results. He has a different year Miata than I do and had to use the 2" in an existing location, I do not. I could use a 3" or 4" full range and mount them as close as need be where his spacing was farther and not as ideal. Since one of the advantages of a FAST is keeping the crossover point out of the mid frequencies I'd think going with the larger 3" or 4" full range would be a better idea. I will Bi-Amp these with an active crossover or a PLLXO. The door will also be the enclosure so both drivers will need to be compatible without a properly built and/or vented one, maybe the full ranger can be accommodated. I'd prefer to just use any of the many wonderful designs, like Tysen, in the FullRange section but they have all been meticulously designed and both drivers are in very well designed enclosures.