Many parts will need to be hand made, but with current prices I am unsure if you can get into one for much less. Everything has a base price. Look at the Shelby world for examples of that. There have been cars like Cobras and gt 40's with far worse damage that are now resurrected. Even totalled Panteras are bringing close to $40k and margins are much tighter. Get out the mallets, and metal brake. Maybe the guys across the pond can fab up a door. You can't have a car worth 400k and expect to buy everything off the shelf. Deep pockets and effort will be required, but it's doable. Hell there's hot rodders shaping metal and building half million dollar cars everyday. Having another Mangusta around at the sametime though for proper referencing would probably make a world of difference.
The car still looks dam good in green.