I have a '99 civic coupe and a very tall husband. The infant seat was almost do-able, but there was no way it would fit behind him, as he barely fits with the seat all the way back. I'm much shorter and was a bit squeazed in myself with the infant car seat behind me. A smaller rear facing convertible sort of fit in the middle, but encroached on the front seats. Putting a baby in the back in that convertible seat was damn near impossible. Remember, 2 door coupe, and I was no longer very flexible, and had a c-section. I felt like I was bending like a pretzel getting back there with baby and seat. Getting back out was like a birth experience for myself. The baby bucket, as we liked to call it, was infinitely easier to deal with in that car, but limited as far as baby size is concerned. (Both our boys grew large very quickly.)
Our minivan held the Graco myride65 convertible, and that barely fit in that big-ass van when it was rear-facing, in the middle. Forward facing is no problem, but the recommendation is 2 years RF. I've read that babies r us will let you try seats out in your car to make sure it fits. There's also a website somewhere with carseat compatibility with different vehicles.