If you even thought of asking this question, 3dr or 2dr isn't
going to be suitable for you. Of course it is going to be
in-convenient for those sitting behind to get in and out. Also a
drag for the front passenger to get out because those behind are
alighting. Usually those who got got these type of cars (with only
front doors) don't consider the option of taking passengers. If you
are considrate enough to ask here, then you will definitely be
bother by it later.
Just a note, 2/3dr car usually have bigger doors, so it might be
better for you if you are a loner/couple. Secondly, might want to
consider the higher cost of maintaining a sport car as compare to a
sedan. Have you test driven both? I think the feel behind the wheel
will help you more.