Ok, so I have an almost-15-month old dd who weighs 21 lbs and is about 75% for height and currently rides in a Maxi Cosi Pria 70 as she has since birth. I am really happy with her seat. I chose it before she was born because it A) could hold a newborn, and B) had a high rear-facing capacity. At that time, I was planning on rear-facing her until maybe age 2 or 4 max.
Now, fast forward several months, and the more research I have done, the longer I'd like her to be rear-facing. Age 4 minimum, preferably longer. And I'm expecting another baby in the spring, so I have to buy another car seat anyway. I am leaning toward buying my dd a new seat and passing down the Pria 70 to the new baby. My US options are: another Pria 70, Clek Foonf, or a Radian. I am leaning toward the Foonf, but it does have downsides, particularly the fact that it sits up so high in the car. I have a mini van and it is already hard enough to get her up into her current seat.
So I've looked at importing a Swedish car seat. Something from http://shop.carseat.se/car-seats/, like maybe the Britax Max-Way (but I'm not set on that one). The prices make me cry, but I'm hoping that the grandparents will offer to buy us a car seat as they did with my first. I am aware that it is technically not legal to use a Swedish seat in the US, but I am under the impression that the Swedish seats are much, much safer. Safety concerns me much more.
What I'm wondering, though, is: Will a Swedish car seat give my dd that much more rear-facing time than, say, the Foonf? I am more concerned with maximum height than weight.
Wife to my best friend, mama to DD (6/29/12)
With all the options out there in the US now I would not import and illegally use a seat. There are plenty of seats to get your daughter to 4 rfing, and possibly beyond that are perfectly legal. Now 10 years ago, I might have given you different advice. As far as seats, I would get a radian over a foonf any day, unless you have a shorter, chunkier kid (which at only 21lbs at 15 months is not the case - my boys were both over 30 by then!) or a child with a really long torso. The rfing height limit on the foonf is 43". For the radian it is 44" OR 1.5" from the top of the shell. The radian also sits lower in the car, and you can use the angle adjuster to get it more upright. Fwiw, none of my kids would be able to rf in either of those seats to the max rfing weight limit. Most kids outgrow by height first, and I would bet your daughter will too.
The reason I am so strongly considering a Swedish car seat is the maximum height, not weight. I think the max weight on the Foonf or Radian would be plenty sufficient for my dd. I have a long torso, so I suspect that my dd might as well. But I'm not totally sure that something like the Britax Max-Way would have that much more room than say the Foonf. If anyone has experience with a Swedish seat as compared to the Foonf or Radian, I would love to hear from you! I want a seat that will absolutely get my daughter to age 4 with room to grow. I'm glad to hear from others that their older (4+) children still fit in the Radian.
The other reason I'm looking at the swedish seats is that they are built and tested to much more rigorous safety standards. Such as the "Plus Test" which (from what I understand) is the strictest crash test in the world, and measures forces to the head and neck in high-speed impacts.
If I can get what I'm looking for in the US, then that's definitely what I'll go with. I just don't want to miss out on something better just because it isn't sold in this country. (To be clear, it isn't illegal to buy a car seat from Sweden. It is technically illegal to use one only because it hasn't met US federal regulations, but since it seems that Swedish regulations are stricter, I'm not worried about that.)
Wife to my best friend, mama to DD (6/29/12)
For what it's worth, my friends had their four-year-old in a high back booster all summer while they were here. The mom is a pediatric nurse working on her PHD.
If you're concerned with the max height versus weight, then you should look at the Graco Size 4 Me/ My Size 70/ Headwise or Chicco NextFit. They only rear-face to 40 pounds, but the NextFit has the same shell size as the Foonf (with no 43" maximum) and the Gracos can hold an average height 7 year old with no problem (rear-facing).
I would not illegally import a seat.
The Britax Max Way will give you more room than the Foonf. It's also passed the Swedish Plus Test at the Gold level, which no American carseat would pass. However, the Foonf has passed the NCAP test, which is more extensive testing than most seats undergo - and when Consumer Reports subjected infant seats to that test, 10/12 failed! So it's probably the best option if you don't get a Maxway or Besafe swedish seat.
You might want to look into the Max Fix. It has an even taller shell (30"I think) and no 1" rule (both the Maxway and Maxfix are top of shell level with the ears/eyes...that's why you get more time without a massive shell)