Anyone used a Britax Infant Positioning Insert?

[Meredith&Alexander]

Anyone used one of these?  Looks promising:

http://www.amazon.com/Britax-USA-S844900-Infant-Positioning/dp/B00422M5JQ 

A review:

http://carseatblog.com/7148/britax-convertible-infant-positioning-insert-and-cupholder-review/ 

Currently, we have a 2.5 year old Marathon and a 2.5 year old Regent (both replaced by other guy's insurance after an accident). So plenty of life left in both of them. My plan is to put the new baby in the Marathon with the infant insert, 4YO DS2 in the Regent, and 7YO DS1 in a belt-positioning booster.

My other two guys have been over 8 lbs at birth, tall in the torso, and we don't take them out in the car at all until they're 7-10 days old. In a pinch, I can send DH to the store to get something else if we decide that absolutely won't work for this baby.  We're in a huge metro area, so there's no lack of choices if we need something else on short notice.

Does this sound like a decent solution? Of course, this all assumes that I have a vehicle that can fit three children by August...  

[mama2soren]

Hmm, looks interesting, for sure!

I'm not convinced it will work for your case, though.  It says it's only been tested with the new generation seats, which your Marathon is not, if it's 2.5 years old.

What car do you currently drive?  There might be a way to get a comfortable 3 across in the car you already have (though, you'd likely have to buy at least a couple new seats... cheaper than a new car, though!)

[Meredith&Alexander]

Aww, shoot.  I might try and get my hands on one in person, just to see how it would fit in it.

I drive a Honda Element, so no dice on getting three in the back, period.  Didn't anticipate another when we bought it!

[mama2soren]

If it hasn't been crash tested with your seat, I would not use it.  Period.  It might not be safe, and would definitely void any warranty on your seat, since Britax specifically indicates that no after-market products be used with their seats, unless they were specifically crash-tested with them.  We don't know if they crash-tested it with their older models and it failed, or if they just didn't crash-test it at all with those models.

[DahliaRW]

You can only use it with the new seats, not the classic.  It is not an option in your case.