I think girls should open the car door for their dates.
And I also think healthy non-pregnant girls should give up their seats on the bus/subway for (same age) guys, as a matter of courtesy and mentchlichkeit.
I disagree. I think anyone should give up their seat for anyone else who needs it more (i.e. pregnancy, age, burdens, etc.) regardless of gender (although, I suppose, in the case of pregnancy, it has to be gender-based). I don’t think a healthy BY girl should give up her seat for a yeshiva bochur (all other things being equal), nor do I think the reverse should happen as well.
Of course, if a person wants to, they are free to give up their seats to whomever they want.
The Wolf