The G is there because the inside bit that scoops the air is shaped like a G.
There were 500 G40s in Britain in the 86c (mk3) Guise, not sure about Europe. In the mk2 version I believe there were 250 in France and 250 In Germany. I have a G40 take a look at my site if you want to see it
www.geocities.com/ereeiz you will need to change the page no. manually in the address after page 5 (goes up to 14 or 15).
Take a look here for a G40 tuning place in England:
www.pitstopdevelopments.com/forum
theres loads of us on there with G40s that have hundreds of pics and info. They easily beat BMW M3's and the like once they are 170-200bhp too