The data plate should show SCJ in 99% of the cases. What does the gear code say? That's your answer in most cases (which would be 3.91, not 3.90, or 4.30).
I would appreciate seeing the Marti when you get it.
I saw this car in York this past weekend - similar, yet different (follow linkie):
http://www.torinocobra.com/forum/vie...=1&t=34753
EDIT: I see you've stopped by the site already. :-)