Horst, I am from the wrong side of the world (Australia). I would aggree with the replies so far, but add one other thing, which is probably the most important of all.
Do a lot of research into the build regulations that you will have to comply with as these will determine what you can or cannot do. For instance, in Australia, any kit car has to be registered as an Individually CONstructed vehicle. This means that the cars cannot be registered as a 66 Ford GT, as they can in some places.
In Australia, ICON status means that cars have to comply with the same standard Design Rules as the general showroom models do at the time when the car is signed off as compliant by the supervising engineer before registration. This means among other things, no small block Ford engines.
Another complication starting to arise here with ICON regulations is that the authorities are starting to become concerned about builder content in vehicles as kits become more comprehensive, and closer to completed before delivery.
These factors may not affect you in Austria, but I would strongly reccomend that you intensively research the local regulatory environment first, and then if you proceed, to select your kit so that you know from the outset that it would comply with the prevailing regulations.
Also, since it is not always possible to forsee changes to regulations, once you decide to proceed, try and get the car roadworthy and registered as quickly as possible, and then go back and spend the hours sanding and painting and detailing the fitout. This way you limit the build time, and changes in regulations while building won't impact you as heavily.
