Well there really is no reason you *need* britax seats. But if you can afford it, I highly suggest getting them. I truly feel they are safer, not just from crash test ratings, but because they are simpler to install, therefore less likely to be used wrong.
If your DD is very tall in the torso, it will be worth it to buy a britax regent which has the highest harness slots of any seat. If you shop around, you can find them as low as $200 with shipping. If she's leggy and not too terribly tall in the torso, you can buy something less pricey, like a cosco apex for $100 (which needs headrests behind it) or a sunshine radian, which you can get as low as $180 on sale. Both harness to 65 lbs I think and do not have as high of harness slots as the regent.
If you expect the boys to be tall too, then one of the britax convertibles that harness to 65 lbs will be worth it. Yes, they are expensive, but they have the tallest top harness slots of any convertible on the market, I think.
Or you could get something cheap for the boys right now, like cosco sceneras ($40-50) and put more money into Britax regents (or whatever they will be called in a few years) later. The cosco scenera only harnesses to 40 lbs, but it has higher harness slots than any other 40 lb limit convertibles and it rf's to 35 lbs, rather than 30 or 33 lbs.
Any way you work it, your DD needs to be harnessed and your twins need to be in convertibles, whether you decide to buy one or two new ones. Good luck!
What kind of carseat do you already have (your dd's old one)?
If your DD is very tall in the torso, it will be worth it to buy a britax regent which has the highest harness slots of any seat. If you shop around, you can find them as low as $200 with shipping. If she's leggy and not too terribly tall in the torso, you can buy something less pricey, like a cosco apex for $100 (which needs headrests behind it) or a sunshine radian, which you can get as low as $180 on sale. Both harness to 65 lbs I think and do not have as high of harness slots as the regent.
If you expect the boys to be tall too, then one of the britax convertibles that harness to 65 lbs will be worth it. Yes, they are expensive, but they have the tallest top harness slots of any convertible on the market, I think.
Or you could get something cheap for the boys right now, like cosco sceneras ($40-50) and put more money into Britax regents (or whatever they will be called in a few years) later. The cosco scenera only harnesses to 40 lbs, but it has higher harness slots than any other 40 lb limit convertibles and it rf's to 35 lbs, rather than 30 or 33 lbs.
Any way you work it, your DD needs to be harnessed and your twins need to be in convertibles, whether you decide to buy one or two new ones. Good luck!
What kind of carseat do you already have (your dd's old one)?