[Scuderia_Turini]

I have to admit some prejudice here (I own a Pininfarina car :-) and have a Sigma similar to the one pictured.

The SIGMA concept car was created at the height of the Jackie Stewart led F1 safety campaign, although Paul Frere was the racing driver in the "committee".  

I saw the Sigma in 1985 and don't recall it being particularly flashy.  I just found the 1977 magazine cover below.
Don't know if the Sigma influenced any changes to F1 cars, it probably got suppressed as costing too much to be viable - different times...

Leo