Weather, I like your ideas, it would definitely be a shame if the pages were taken over by non-credible information. Ill certainly be deleting or moving any snake oil type mods people put up.
Tonight I have taken a crash course on wiki page writing and set up the main page which you can find here
Car Modifications Main - EcoModder
I would go for your idea number 2 personally. If I can work out how I will put it in. Takes a bit of reading to work out all the features.
Anyway feel free to have a look and make any modifications you like.
I added the unproven mods section so that some new ideas come into the pages and it gives me a place to put new ideas that nobody has any data on. If I see some snake oil concepts I might make a new section "unscientific ideas" or something to that effect.
If you want to make changes or learn how to make new pages there is a manual at the bottom of the main wiki page (the page linked to by the link in the title bar "wiki")
I am going to start on the template now, see how far I get before I head to bed