I've been trying to find a way to get three car seats across our 2011 Suburu Outback, and we finally did it! I found it so helpful to read posts from people detailing their make and model car, and the exact seats they used.
We can fit two Diono (Sunshine Kids) carseats behind the driver and in the middle, and a BabyTrend infant seat behind the passenger's seat. Its tight, but it will fit!
Re: 3 car seats across
Pp the Radian can be a good convertible. But I would not be moving any convertible regardless from car to car. If you can only afford one Radian I would seriously consider getting a few less expensive longlasting seats. depending on your lo stats you should look at the Graco MySize/Headwise/Size4Me, Cosco Apt or Evenflo Sureride.
If you are looking for a car seat that you can move between cars fairly easily, look at the chicco nextfit. It is super easy to install and takes up less space from to back than the radian, at least in my cars. The nextfit is heavy though and wider than the radian.
Diono seats are super tall. That may be a bit of a problem if you want them rear facing in a small car, but we will have both of ours FF so I don't know. I'm excited that they are tall because they will last a really long time.
They aren't easy to transfer--pretty sturdy and heavy. But I wouldn't be able to transfer our other carseat, a Britax, either, so I don't know if Diono's are better or worse than other brands. For us, the most important factor was it being narrow, which Diono's certainly are!
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EDD August 11, 2013