Car seat shuffle!?!

It's going to be time to play the car seat shuffle in a couple of months, and I am hoping to figure out what my best options are so I can look for sales. In our main car (2012 Elantra Touring), I have the Keyfit22 for baby and a ff Foonf for my 3.25yo. In our second (2003 Toyota Echo) car we have the Diono R120.

So my question is, what are my best options when the baby outgrows the Keyfit? Should I look at moving my 3.25yo to a harnessed booster and using one of the other seats for baby? If so, which booster is my best best? ODD is 39.8lbs and 38" and, from what I've read, the R120 doesn't last as a booster. If we need to purchase something for her, I am hoping it will be the last thing we need (harnessed HBB that coverts)...if so, price isn't a big issue. Alternately we could get another carseat for YDS if ODS can stay in the Foonf or R120 until the time when she would be ready for a LBB. As we did with ODD, I plan on RFing YDD until at least 3.

Radians make terrible boosters, and Foonfs aren't boosters at all, so yes, I'd look for combination seats for your older child. Have you started here already?

http://carseatblog.com/carseatblogcoms-recommended-car-seats/

Thanks! I took a look...I'm leaning towards a 3 in 1...if that will last the longest. I like the frontier but it is pricey with, as far as I can tell, no backless option. The Argos also looks pretty good. Is it worth getting something that does all 3? What should my priority be with a booster? As I said, she is a big 3.25. She has been over the 90th percentile since birth and I don't see her slowing down.

I would not let backless options or lack thereof influence your decision. Backless boosters are so cheap, and the backless option on 3 in 1 car seats often doesn't meet your exact needs. Unless she's extremely long waisted or you don't expect her to be booster ready at a typical age, the height on the Frontier is probably overkill, but it really is a great car seat. (We love ours for my impulsive, huge, long waisted DS1.) The Argos would probably meet your needs just as well.

I think it makes sense to pass both of Those nice convertibles to the baby. I agree not to worry about the backless booster option right now. I have yet to see a seat that does ff harness, HBB and NBB have a NBB portion that I really liked. I like a cheap little NBB better, or your daughter might even need something like the incognito for her NBB when she outgrows a HBB, because she is in a high percentile height/weight for her age.
It seems like the NBB portion or most 3-in-1 are pretty tall boosters that might actually lift a tall child up too high in the vehicle seat! You want her ears to still be below the top of the vehicle's headrest. The incognito doesn't lift very high so it is helpful in that situation.

So anyways, just my long-winded way of saying to get whatever combo seat you like best and don't worry about needing to buy a $14-$20 backless booster when she's 6-7-8 years old. You may find you want a small little spare booster around that time anyways for grandma's car, an extra for a friend, etc.

If you want to harness for a while longer, a frontier will be your best bet. The Recaro combination seat has pretty tall slots as well, I think.