Yea Ali, the static scale fans (picture attached) that you may have seen on my web site: [link]http://jetadic.com/[/link] are only for show and they only fit the G-4 Nacelles.
The mockup spinner, screen, etc. (picture attached) that comes with the G-4 MIBO Kit has no measurable effect on the thrust....also only fits the G-4 Nacelles. Roger