No sides where? Near the head? NEar the legs? Or the fact that there's no base that makes it sit up high?
If he's worried b/c there doesn't seem to be as deep sides next to the head, you could get the RXT version, however, the headwings don't stay up as well as they should (per carseatblog's review, I believe) and you'll lose a little bit of how long the seat will last b/c they take up some of the height growing room. Also it's important to realize that ANY 5 point harness seat provides some of that side protection just by what it is.
There is some seat that comes up near the legs.
If he's worried that it sits very low to the car without a base, that's actually a really good thing. Number one: fewer connected parts is good. Number two: there was some evidence in testing a while back that indicated a popular seat brand that sat high on a base didn't do very well forward facing, and concluded it was at least in part, I believe, b/c of it sitting so high on the base, higher center of gravity and all. So baseless is great. Also makes it easier for mom to put child in, and for the child himself to climb in without help once he's old enough.
There have been several crashes of members on this board in the last year (unfortunately) and Radians have been involved in several of them - and protected beautifully. I used to never recommend them simply b/c they can be difficult to install in some vehicles. But now that I have one, I'm sold.
