There are many cars where the choice of make is just a sticker, between Ford/Mercury, Peugeot/Citroën/Fiat, etc.

ok but in most cases when it's not really determiable Custum made designation then so Custom Made Silhouette. In NASCAR for example the only difference between the Chevy and Ford are the stickers the rest , body etc are identical, so unless you see some sticker or car determien from race number ther eis no point really, situation gets even worse for lower less profile series like that

in the lower racing series like dirt racing for example manufactuerers aren't involved, the workshop put some random body cos the rules require to have a slight road car look

so for such cases all this should get this designation
http://imcdb.org/vehicle_621904.html
http://imcdb.org/vehicle_638314.html
http://imcdb.org/vehicle_493632.html
http://imcdb.org/vehicle_491112.html
http://imcdb.org/vehicle_491111.html


this one perhaps Pontiac Silhouette ?
http://imcdb.org/vehicle_493637.html

But they are advertised by the car makers as being one of their cars, so listing them under the original name is still logical.
But indeed previously it was discussed of listing these with a Silhouette suffix rather than a NASCAR suffix.
But that will be probably improved later anyway when there will be a more advanced system for model listing.

well wanted to suggest that all race cars named NASCAR on IMCDB should be changed to what I suggested since many of them have nothing to do with Nascar really like this things

http://imcdb.org/vehicle_493637.html
http://imcdb.org/vehicle_493632.html

this cars have nothing to do with their roud coterparts just some (very) superfical resemble by their fibergalss/ plastic cover

and would also eliminate the need to guess which road cars they are suppsed to be based on like in this examples

http://imcdb.org/vehicle_638314.html
http://imcdb.org/vehicle_621904.html


and best way to describe this graphic, chassis is tube frame and some fiberlass cover to give it some resemble to road car but actually they have nothing to do with them
http://www.virtualr.net/wp-content/gallery/677/jaguarrenderv2bb8.jpg

or this pic
http://www.casc.on.ca/forums/attachment.php?attachmentid=5397&d=1320517405