15's ported or sealed

im building a box for a friend of mine. he's putting 2 punch classic 15's in his trunk. i'm building the box out of mdf b/c i dont have any experience with fg. my question is do i port it or seal it. and another question do i face the speakers to the seat or out the trunk? my friend has a ford taurus if that helps. its gonna be really tight!! any help would be cool thanks.

oh yeah if i port it where how do i know how big and where to put my port holes?

Me personally I like all my boxes sealed.  but you have to take into consideration your airspace and how big the box is going to be.  See you use a ports if your box is going to be smaller then your required airspace and the port acts like the remaining airspace needed.  Also my expereince I have always found it better to face the speakers toward the back of the trunk that way the sound waves can bounce off the back of the trunk and work like a reverb and make your sound wave louder in retrospect to where the driver seat is and the front of the car.  I think this website has a port claculator so you can determine your port size also.  If you are considering a port research doing a channel style port.  just some ideas from me.