First off congrats on keeping her rearfacing, and keep her rear facing to the max limit of the seat weight limit, or unless she out grows it by height first.
First Years True Fit $190. Tallest shell of any convertible. 35lb rearfacing 65lb forward facing. It has a deep shell, more leg room for longer rearfacing. low profile so its easier for child do climb into. no need to re-thread the harness, just pull two knobs to adjust the harness, easy install with built in lock offs for rearfacing and forward facing. Energy absorbing foam (the stuff helmets are made from). Only problem while rearfacing is it can be tricky to tighten the harness because of where the harness adjuster is. There is a new true fit coming out with the Anti Rebound bar. I am assuming it would be easier to adjust the harness since it should be higher up on the seat because of the anti-rebound bar. The seat is good for 7 years from the date of manufacture, unless in a car crash then you need a new one. which insurance will cover.
Then there is the Britax Boulvard $309 rf 35lb ff65lbs My 2.6yr old 329lb 31in tall 15in torso is still RF in this seat and will be until 35lbs. she is a peanut and will out grow it by weight first RF then by height. Normally car seats are out grown by height befor weight. This seat installs like a dream in any car. I can RF in my Pilot out board using LATCH and I also Tether to the front seat by wraping the D-Ring (it comes with the car seat) around a bolted down part on the front seat. I can install it RF and FF in less then 2 Min and it is soild install. I would buy this car seat again in a heart beat. When its time for my daughter to move up to another knotch on the harness I just turn the knobs and I am done. I have no problems tighting or losening the harness adjuster. It is $$ but its piece of mind, easy install, and my daughters head never slumps when she falls asleep (which is daily).
If your on a budget there is also Cosco Scenera 35lb rf and only 40lbs ff. $70. Safety First Avenue 35lb rf 40ff. $95 at sears. the difference between the 2 is the Avenue has energy absorbing foam and the Scenera does not.
After your child out grows these seats your daughter will need another harness seat like graco Nautulus, britax Frontier, or a new seat on the market. I will not put my 41 lb 5yr old daugher in an Adult seat belt in a booster. My 5yr old rides in a Graco Nautilus and Britax Regent. These seats are fine to use. All car seat must pass the same test. They are not made public so we dont know which seats did better or which did worse. all seats passed
I live in the goose creek area and if you need any help at all installing your seat, please feel free to ask me I am more then willing to help you install your seat the right way. Less then 1in of movement AT THE BELT PATH. Also check out car-seat.org. there are car seat techs there that can help you choose the right seat for your child, budget and car. I have learned alot from this site.
The safest car seat is one that is used right every time, chest clip at arm pit level or the chest not the belly, harness tight and less then 1in of movement at the belt path.