What's it worth. (Insurance and mortgage queries)

We are applying for a silly big mortgage at the moment and a question I keep having to answer is the value of assets.
I know sort of what it's taken to build it which covers the insurance side (agreed) but that's only half the story.
So what's a race only (sports sedan)MK1 escort with a new built 400ish hp motec m130 controlled rust free freshly painted with all the bells and whistles worth.
Ap racing brakes, Bilstein coilovers, 6 link holding Hilux axles with kaaz lsd, tilton hydraulic clutch bearing, ap triple clutch, obp adjustable alloy pedal box, new wiring throughout, big alloy radiator and intercooler and oil cooler, new carbon winged seat, 6 point harness. New fuel cell, pumps and piping. 15x9 rims with new 205/50 and 225/40 semi slick race tyres, RSR front spoiler, excellent bumpers, steel arches?
I'm saying 40k on the applications but is that too conservative or silly optimistic.
I am not looking to sell just want it insured properly and to maximise our asset claim as the banks are currently expecting real figures not the made up stuff of a decade ago.
JP
I know sort of what it's taken to build it which covers the insurance side (agreed) but that's only half the story.
So what's a race only (sports sedan)MK1 escort with a new built 400ish hp motec m130 controlled rust free freshly painted with all the bells and whistles worth.
Ap racing brakes, Bilstein coilovers, 6 link holding Hilux axles with kaaz lsd, tilton hydraulic clutch bearing, ap triple clutch, obp adjustable alloy pedal box, new wiring throughout, big alloy radiator and intercooler and oil cooler, new carbon winged seat, 6 point harness. New fuel cell, pumps and piping. 15x9 rims with new 205/50 and 225/40 semi slick race tyres, RSR front spoiler, excellent bumpers, steel arches?
I'm saying 40k on the applications but is that too conservative or silly optimistic.
I am not looking to sell just want it insured properly and to maximise our asset claim as the banks are currently expecting real figures not the made up stuff of a decade ago.
JP