have a ? bout enclosure and cap

hello i have 2 ?'s for you  first off i am installing a system in my '99 eclipse and i am to cheap to pay someone to install it for me so ? number 1...i have 5 audiobahn subs 1 is a flame sub other 4 are not i figure each will be in seperate sealed boxes with the flame 1 in the middle. now the flame 1 i want upside down so i can see the flames. ive seen it dont  it lots of systems but i need to know how?  i mean i know the magnet part will be out in the open, but do i need a certain amount of space {box} on the front of the sub. i plan on having the face  facing down in where the spare tire is supposed to be but must i build some kind of box under there for the front or just make damn sure i keep it air tight and it be just fine. now for the second , i have 2 stiffening caps 1 i want to be seen the other not  now how do i connect the 2 together  . ive tried it once but i dont think the 1 that was hiding was even workin because the l.e.d +voltage wouldnt come on.  could anyone please help me out it would be greatly appreciated  thank you