There aren't many of those 6 series around to work with. Better would be to do the E30 M3.
I would add the Ford Mustang, preferably just the first generation (1964-1969), although the aftermarket is already very lively for these cars, and a handful of specimens (esp. the sought-after versions: Boss, Fastback, Cobra, etc.). I might also give some though (though I'm not absolutely convinced) that the Volkswagen Beetle belongs on this list. Both cars meet all the stated criteria.