For those with the Diono Radian RXT Convertible as rear-facing, did you need to buy and use Diono's angle adjuster? (I am hoping to install in the middle.)
Btw - the Chicco Keyfit 30 rear-facing infant car seat has been great for us so far! It is installed in the middle, and still provides me with ample leg room in the front (6'0 tall). I initially installed it using LATCH, but after getting it inspected through my county's free inspection program, they advised that it was not a tight enough fit and recommended using the seat belts instead, which ended up providing a much more secure fit and immovable.
If you're installing it in the middle you'll probably be able to get away with not needing the adjuster, but behind a seat it's absolutely necessary unless you are tiny. In fact, we need to buy a new one because the old one has been in use for a couple of years now and is crushed pretty badly so it's causing the child seat to lean towards the seat more than I'd like it to.