Beginner with fiberglass???

Hi everybody........I am new to the board here and have found alot of useful information.  I am also new to custom installs.  I have a 2000 Grand Am SE and am installing the following...........

- 1100w Profile California Amp

- 4 10" Audiobahn subs

- 1 600w Jensens Amp for 6x9's (will be hidden)

My problem is this.  I am going to have my buddy do me up a box.  I want to fill in the trunk with fiberglass and bond it to the trunk walls.  Is this a good idea to do or not?  What are the odds of it cracking or breaking apart from the trunk walls?  Like I said, I have never done anything like this before and have ideas of what I want it to look like.  Just trying to get ideas of the best way to go about making this.

Thanks for any help...

if you do that then it is permanet and wont ever come off... you should think about making a mold this way the fiberglass can be removed from the car...  this is done by taping the area b/f you glass so is wont stick to the side of your car. 

check this out it might help a beginner

http://chris.pfharlock.com/glass/

good luck!