I find it hard to believe anyone is in and out of a car more than I am. I drive about a 1000 miles a week on average for work. It's actually the opposite for me. I used to carry exclusively at the 4:00 position. I had carried there for several years. I started having pains in my lower back on that side about a year ago. Come to find out it was because it was putting my back in a slight bind. Once I stopped carrying in that position my back quit hurting almost immediately.
If you will find the right holster and position for you, AIWB is great. I can actually draw very fast while seated in a car carrying that way. Drawing seated in a car from the 3-4:00 is pretty difficult. You have to lean very far forward to draw from either and there is no easy way I have found to get around the seatbelt.
I think 2:00 AIWB would be great provided your barrel/slide was very short and didn't poke you in the leg. I don't own any subcompacts. I think it would be hard to do that with anything else.
I have tried many OWB holsters. I finally gave up and decided that I just hate them. The best I have tried is a Raven Concealment. But honestly I rarely ever carry in one. Also some people talk about buying bigger pants for IWB carry. I never have, but I don't wear my pants skin tight anyway. If you carry at the 3:00 position it will at the least pull all the slack out of your pants. 4:00 seems to me to take up slightly less room in your pants. AIWB takes up no room, atleast for me. I can tighten my pants normally and still get the gun/holster in there. I think rather than pushing my pants out it's pushing my gut in.