I have made this at work, its an exact copy of a GTM Chassis plate that I took off a photo given by West, this is done in Auto CAD and to scale, my one on my car is knackered and I wanted to see if I could make another, I'm going to look into gettting one laser etched if I can find someone to do it or I may just give it to a signwriter to do. If anyone wants a copy email me and i will send a copy of the file.
Sorry forgot to add, obviously the stamp lettering should be blank (i.e. aluminium) and any of the solid black would be coloured black, but for ease of reading I have left it as is, I'm sure you get the jist.
