We drove the 300E (now for sale) all the time with 2 full car seats back there (2 adults, 2 kids). I say full car seats because it's not just those booster types. On occasion there was still room for an adult to squeeze in the middle between them. So for your purposes, with only one car seat back there, I think a 300E would be just fine. Aside from about 4 or 5 inches more leg room, there is also about 2 to 3 inches more room from side to side, possibly more. I recommend that you test drive one just to be sure, but I wouldn't think you'd have any problem.

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