Thanks for all the compliments, and I'll try to answer all the questions.
I started the switch from plastic car kits, to scratchbuilding with cardboard, back in 1980, so I could have models of the cars I like. Please see my entries on the members gallery here on Model Cars Magazine Forum.
The spark plugs are cut from Q-tip swab sticks, and the colored paper is cardstock. Plastic transparency makers are the "glass".
There are IPMA meets that now allow paper model entries. Paper modeling is growing in popularity, due to:
lower costs;
easy workability, especially for scratchbuilding;
and an increasing variety of commercially produced paper kits (mostly available in downloadable format, or CD's, or mail order).
There is a card modelers' forum on Zealot Hobby Forum, and an online club called Papermodelers.com I'm a member of both cardmodeler sites. They are very active, with a few thousand members each, mostly from the U.S., U.K., Canada, Australia, New Zealand, and Europe.
Thank you again for your interest and encouraging comments.
Mark