Note: I have copy and paste it. Nothing is done by me.
I am sharing it for the knowledge.
I decided to make a Fiberglass sub box for my tazz and share my experiance as a tutorial.
This is how it came out.

What you need:
11L of Fiberglass resin
Hardner
6m of Fiberglass mat
5 Roles of thick Masking Tape
10 meters of Foil
Thinners
Brush
Wood
Stretch material
Carton Boxes
BodyPutty
Spot Putty
Paint
Wooden round sticks
Sanding Papper
And you need alot of paitance for the job ahead!!!. And you are going to itch a lot!!!
Firstly I took out my old Box.


Because I did not want to struggle to take out my spare wheel I
decided to mount it to the back of my Back seat, so that when I
leaned the seat forward I could easy retreive the wheel.

I cutted out the shape of the wheel in the base wood.

Then I started to build out of carton box for the moulding of the Fiberglass.


Just for curiosity I then placed all my equipment in to see how it would fit best.

Then I started to apply the whole trunk spase with masking tape.
After the whole trunk had masking tape inside I covered that with a layer Foil.
Note: You have to do this to be able to remove the moulded Box.
And believe me with all the precausions I took I struggled to remove the box!.
I then started to paint Fiberglass mat and ressin to get the inside mould of the trunk



After 3 layers of Fiberglass you can remove the fiberglass mould from your trunk

Now you must apply3 more Layers to the box.
With a permanent marker you can scetch where you need to cut off the excess fiberglass


