I have a 2007 toyota camry and I'm having to put 3 seats across now (3rd baby due in February).
I have a 2 year old, and 3 year old, so they are in convertibles.
I have to have at least 1 sunshine kids Radian to be able to do 3 across in my car.
I already had a Radian before getting pregnant, but if I didn't, I probably would have had to get one, I don't think I could have fit 3 across without it. It's already a tight fit as it is, but it does fit.
The seats I have are: Radian 65 for my 3 year old, Fisher Price Safe Voyage Deluxe (basically like a Britax Marathon) for my 2 year old, and a Keyfit 22 for my new baby.
I had a tech help me install them to check if they fit together, and we found out that once my baby is outgrowing the infant seat, keeping the 2 convertibles I already have, I can either get another Radian, or a Britax Marathon. Some others might work too, but thats just what we had available to work with when trying to figure it out.
What seat is your 3 year old in right now?
Here are the pics of the different ways I can have the seats in the car. The first pic is how we have it right now, and will have it for just a little bit after the baby comes, then we will switch it to the other way.