Fitting a car seat...I know it's stupid...
 

Didn't look close enough when I was test driving to see where the child seat LATCH attachments are... is there one for the middle of the backseat? or only the outside... Not a good solution to the cramped backseat, but it might be A solution. If anyone who has an IS can take a look in the car or the manual that would be fantastic.

And I already know the car wasn't designed for hauling a family, I've got other cars for that... just an inquiry. :)

Probably not for the middle seat. However, couldn't you just use the INNER latch anchors on the outside seats to place the baby seat in the middle??

Possibly, but I know in the RAV it was a hell of a stretch just to get the latch attached... the strap for it isn't really long. But that's on the standard seat we've got in the RAV now... perhaps the Recaro infant seat being launched this month will be a little more versatile.

child system numbers
 

looked in the manual for ya and only saw child seats in the left and right seats (not the middle)

here are the hookup numbers

anchorage conform to: fmvss225 or cmvss210.2
Child Restraint System conform to: fmvss213 or cmvss213
vehicle conforms to: sae j1819

Hope this helps

Yes... you can, but the top latch will most likely not be attached. I did this is my G35 Coupe to get one more person in the back.

Does anyone know of a car seat that isn't too bulky? I think I might have a similar problem with the IS that I had with my G35, I won't be able to get a third person in the back with a carseat in the middle. Just won't be comfortable.

How is the Recaro Car seat any different?

from the website:
"Each RECARO Young Seat comes standard with the innovative RECARO SIP: the original Side Impact Protection. The perfectly shaped extensive side wings offer extra protection for the sensitive head, shoulder and hip area in the event of a side impact collision. With safety for your child firmly in place, we then turn our attention to other issues that help children enjoy their seat."

and I'm sure it's considerably more expensive! :)

www.recaro-nao.com
then look in "young seats" I'm interested to see their infant seat which is just being released this month as that's what I'm in the market for at the moment.