Need experianced help on close to IB setup.

[Dodgeneon]

Ok, im going to try to keep this as simple as possible since its my first post and im really hoping to get some good answers here.

Im designing an enclosure for my subwoofer in the trunk of my car. Done many types before basically all but infinite baffle. Now.. I am designing an ib setup in my car since i now have a 6 month old and need a trunk often.

I was originally just going to mount my sub (Mach5 maw 15") behind my rear seats with a double .75" mdf baffle and seal off the trunk from the front. I have most of it deadened already, so there is not alot to do in that aspect, but i will be fiberglassing it all to totally separate the trunk from the passenger compartment. I am set on this idea itself, but after considering output, which i know ib is lacking in i am now thinking or running 2 4" ports through where my rear factories where ( i have a true sq setup componants up front and rear sub stage) and turn the trunk into a ported enclosure. I know there may be small leaks around where the trunk closes, but due to the dual 4" ports i know alot of the pressure will be going through them first due to lack of resistance. Is this a viable thing im thinking, surely i am not the first to think suck a thing, but trying to find any info on this if like pullling teeth.

If anyone has any insight on how this would sound/output compared to just sealing the trunk and running an almost ib setup would be, i would greatly appreciate it.
And mods if this is the wrong section, i do appologise, but its seemed the most appropriate after reading each section description.

Thanks all.