Well as the Tall Guy in this (electronic) room I'll weigh in and say that I'm 6'6" and no part of me touches the headliner now or ever has in my '73. May have something to do with tipping the scale at 280, I dunno...
But I'll also say that both front seats are due for rejuvenation including both covers and cushions.
Sunroof-equipped Bimmers and Vee-Dubs (I've had numerous, why not, in Hawaii?) cost about 1.5 inches of headroom, current example being my 2002 325xi that my daughter drives is a tight fit for my head and shoulders. OTOH the '98 Benz C280 of the wife fits fine, and seats are in good shape.