Having a Civic as well ('99), the seats are the same, I'd say either Evenflo Triumph Advance or Marathon. I'd be hard pressed to decide between the two - Triumph Advance is not a second choice to Marathon, its just a different one, with some features that are really cool that Marathon doesn't have, and Marathon(MA) has those great lockoffs that Triumph Advance (EFTA) doesn't have.
The Britax Marathon/Boulevard/Decathalon (These 3 are the same seat, just different features. The Marathon a wide open easy to route belt path, which makes using it correctly a lot easier, as do the built in lockoffs, which mean you never again have to use a locking clip. Because of the way the base is made, it fits in most cars. And, it is worth the money, b/c it lasts usually twice as long as most other car seats lasting a baby till they are 5-6 years old, where most at Walmart will only last till 2-4 years old. Rear faces to 33lbs, then forward to 65lbs. and top slots 17inches tall, lasts most kids to ages 5-6 years old.
The Evenflo Triumph Advance (not the original Triumph, make sure it says Advance) is a great seat. Top slots 17", harnesses to 35lbs rear facing, and 50lbs forward facing. Wide open belt path, easy to install. The harness adjusts at the front of the car seat, you don't have to take the car seat out of the car just to raise/lower the straps. It has infinite harness adjustment so the harness always fits perfectly until its outgrown. You tighten and loosen the harness using knobs on the side of the seat. It can be used in a recline position even in forward facing mode.
You can get Triumph Advance for $150 or less, and it installs easily rear facing in the middle or behind passenger seat. I had my son's behind the passenger seat and people sat up front fairly comfortably, I'm 5'6" and I sat in front of it with no problem. The EFTA will take up little less space rear facing than the MA b/c of its bowl shape. If you really like the MA and money is the only hold back, albeebaby.com currently has some MA s on sale for $199-$209, they may or may not be older DOMs (Date of manufacture), you could always call and ask. albeebaby also has EFTA on sale for $109, orders $100+ get free shipping.