I bought 4 8'x4' sheets of aluminium: 2 mm half-hard for the floor and tank, 3 sheets of soft 1 mm 1050 for the panels. They cost me around £150 altogether. Making ali panels is fun and easy, and even though I've made mistakes, they're not very visible. In the book Chris recommends not bending the side panel where the chassis breaks towards the nose, just letting the sheet finds its own line. I read that advice after I've already bent mine:
I was quite upset thinking I've ruined the looks of the car for good. But in fact even with the far-from-perfect side panels, and the horrid crumbling GRP the car is still turns heads and looks great generally.
Here's my cutting plan for the thin panels:
Doing your own GRP is definitely a cost saving measure. The materials account for about 20% of the price of commercially made GRP panels. To save time and money, make a one off nose without making a female mould. Laminate glass on the buck, then auto filler and paint.
You can use this plan to make a buck of the size and shape of the Triton/SSC/Gillham nose:
http://locost.lt/download/file.php?id=385
25 mm squares, the black lines correspond to 20 mm slices, the red dotted ones are 50 mm apart. I have the vector version somewhere, too. I used the cheapest polystyrene foam and some plaster putty compound on top to protect the foam from the styrene in the resin.