so I have 2 fi bl 15's im looking to do a custom enclosure in the whole trunk(2004 g35 coupe) if anyone could help me get started on some ideas that would be great... thanks

 

Won't fit those

You're looking at 4 cubes per before port and sub displacement. Only way would be a wall.

 

even if it was a sealed box? im not looking to get the full amount of cubes just use my entire trunk fiberglassed or what not... i just need a couple ideas i may just put 1 of the 15's and use all the sapce....

 

Bl's perform poorly sealed

It tells you right on the fi site that its a ported only woofer

 

there would be no way to even get the box into the trunk.

 

Agreed

for spl, i'd do 2 8's or a good 10 in a 4th order

2 10's would be nice, but def wont fit

 

That isn't impossible but crazy and unique costs. It would require a 3-part enclosure and $1500 just as a starting point for the labor and materials in the hands of an experienced fabricator. Know that you will also be adding a couple hundred pounds easy to the trunk and your charging system upgrade isn't going to be cheap.

You can easily figure 3 grand just to get the ball rolling before equipment.

Don't forget 10 bucks for a roll of duct tape for your roof gasket, though