Our second child was the main reason that I went with a JKU in the first place (all of my previous vehicles had been either 2-seater sports cars or regular cab trucks).
I found that I had to put the rear-facing car seat on the passenger side since I felt cramped with him behind the drivers' seat. I like my seat almost all the way back & my wife bought a gigantic Graco seat which meant that I had to push my seat forward a bit for it to fit.
Now that he's in a forward-facing seat, his seat (another gigantic thing
) fits well enough behind mine & he even has a bit of leg room.