Thanks for your comments, gentlemen. Such words from talented artists like you are really nice to read.
NightEye, you're right, that car is really rare. I first read about it in "SportAuto", a famous french publication. Good refpics are hard to find, so fan sites and Flickr are good sources.
The picture you posted is a later version I think : some stuff is different, like headlights covers, side mirrors, lateral air intakes in the front bumper, door handles, and that double bulge on the hood. I'll try to stick to the original design from 1963. Please have a look to the following link to see the whole brand activity.
The Marcos cars 1959 - 2007
greenvampire, I really agree with you. There is plenty of entries so far with rare cars, different kinds of vehicles and great modeling. Nice nice nice !
Here's a little update : bottom of the front bumper, details on side of hood and on headlights... I tried to put on it a white paint, the shader still needs work but that color may suit the car pretty well IMHO.