If you're still looking for ideas, user jedi_sol had one that he took pretty far.
Details: Aero Sol *SOLD* - 1993 Honda Del Sol GSR Fuel Economy - EcoModder.com
Looks like he was averaging 42 mpg out of it before he sold it. It should be noted that it did have a totally different engine from an Acura, but he did do aero mods to the body. And I believe most of it was documented somewhere here on the forums.