We have a Evenflo Triumph in the back of our Hybrid. Currently in the rear facing position. It fits fine - although I'm only about 5'-8" so the driver's seat isn't too far back. Actually it fits as well in the the Civic as it did in my 2000 Nissan Altima that I traded in for the Civic - and the Nissan is a midsized car. I don't think you'll have trouble fitting one in unless you're really tall and have the driver's seat back far.

Eric