I haven't even sat in our 500 Lounge yet

but even at 6' I find the Sport has plenty of headroom.
Traditionally, cars fitted with a 'proper' sunroof (one that actually opens) will have less headroom than one with a glass roof, such as the standard Lounge roof, where the glass is a fixed substitute for the metal roof of the car.
If you struggled with the Lounge in your dealer's showroom then any 500 fitted with a 'proper' sunroof is going to be no good
