I thought I could answer some of the questions and thoughts above as my brother and I own the car.
The car has been modified, but IMO a great deal of thought was given to the modifications to ensure that no holes were put in the chassis or any changes made to it. The reason the chassis is white is it has been wrapped and removal of the wrap would reveal the carbon chassis.
The current bonnet is made from the mould we had made using the original. We did this so that we could retain the original bonnet with side scoop and put a hole for the exhaust, one for the throttle bodies and lose the side scope which we did not need. The original exhaust has also been kept as this will fit through the original bonnet to restore it to original. The original carbon headlights have been kept and could be fitted in minutes.
The most difficult modification was the dry sump. The bracket to mount the scavenge pump needed to be designed to fit the pump inside the chassis to ensure there were no changes to the chassis (there is not much space and access is very restricted due to the chassis). The oil tank was then designed to fit in the chassis and utilise an access hole that was original to the chassis. All these changes can be removed and the original engine refitted. We have fitted Tillett seats but again retained the original seats.
The only modification that we do not have the original parts for are the rear lights. The lights just fell to bits and we replaced them with LED. I am sure the originals would be easy enough to source.
We also own what was left of the factory spares for the car which include wishbones, uprights, Penske shocks, drive shafts, 2 more sets of wheels and so much more. Frankly, boxes and boxes.
The car is the only FW 400 with carbon bodywork and could be returned to original. That said my brother and I have made some changes to improve the car, but I stress with thought. The Hellier engine with dry sump being the main change which is a great engine. It was rolling roaded a few weeks ago at Northampton Motor Sport at 214 BHP.
I am pleased with the condition of the car and the respect in which we have made changes. My brother and I wanted an FW400 and really did not want to butcher one or work it as a track dog.
We are not under pressure to sell it, as we both have an emotional attachment, and it is still being used. That said too many toys means I need more garage space.
If you have any questions on the car I will try and answer.
Thanks for reading