Very interesting project. I'm sure a lot of us will be following your progress. One question, did you ever consider using a rotary(rx8) engine? I'm thinking that it would fit in nicely with your light weight theme.
06 GT GG, PSS10, Hotchkis, GWR exhaust, RPF1, AD08, IL braces, MS, dptune
91 A CR 5sp, Millen, FM, GAB, MOMO, Panasport, Naca, braced