Ooh, that's another point... since the seatbelts lock at the shoulder, when you put a rearfacing seat in, I'd want built-in lockoffs so you don't have to use a locking clip to prevent tipping.
Now, I can get the Radian in RF (Since I have a 2-door it would be optimal to put it in the center, but I didnt try it there because of the barely tolerable latch install ff there and HORRID seatbelt install there.), but the seat does need to be a bit forward, but it was still fine for DH or me as long as it was the passenger side (lots more spare room there)
and the Radian probably takes up about the same amount of room... of course, the seats are buckety and the 4-door would offer more room, so that helps... (the buckety seats make the seat naturally be more upright and with more room in the 4-door, I don't see why you wouldn't be able to easily fit any large rf convertible.
But again, I would take any seats you have with you... and use those to figure out just what you can fit in there.
Oh... the cobalt has 3 sets of latch, which are very easy to figure out because they are straightforward.....AABBCC, so I guess the lockoffs aren't essential, but sometimes I just find a seatbelt install a little easier, you know??
I was so worried when DH got that car and, except for the fact it is a 2-door making it harder to put 3 in a row, I've just been so pleasantly surprised by it... the room is great, and it just doesn't feel like the small car it is.
Oh... and the trunk is GREAT. I was able to fit the Valco Rad in there with an average size load of groceries.